Decreased player performance can also be caused by injury, there are several cases after a player is injured and cannot return to his best performance. Players who don't participate in the world cup can still control, they can do regular exercises during breaks to maintain their physical fitness.
Not all players who play in big teams like Manchester City, Arsenal, Liverpool and Chelsea are called up by the national team. Those who are excluded from the national team can still do something that can maintain their performance. During the break they will continue to do training with other players, the coach has a responsibility to keep his players disciplined and carry out routine activities with the club.

Professional players will always maintain a special diet and exercise during the holidays to maintain their weight, they will do anything to keep their performance always in the best condition.
Very rarely is there a case like your question, they will not do something that could destroy their career.
Concerns about the decline in player performance after the break are unfounded, i never thought it would happen. All players will continue to do things that can improve their performance during the world cup break.

All Napoli fans will hope that Napoli will always be in the best condition. The world cup has given a bit of a break for players who weren't included in the national team squads that were taken to the world cup. While players who will compete in the world cup will potentially be injured.
Napoli really hope that nothing happens to their players who are defending their country while the biggest football tournament in the world is still ongoing, if one of Napoli players suffers an injury it will greatly affect Napoli appearance after the League starts again.

Napoli which has secured first place with an eight-point lead from Milan, which is in second place, will try to give its best after the world cup break. Spalletti of course, had prepared if something unexpected happened, including the hijacking of his players by another club.
Several Napoli players have become the target of other big clubs, Spalletti must persuade his flagship player to be loyal and willing to help Napoli win the Scudetto which has not been won for a very long time.

This season's Europa League smells like the Champions League, a surprise occurs when there are more big clubs in the Europa League than imagined. What caught the attention of football fans the most in the Europa League was the game Barcelona vs Manchester United. These two clubs competed more frequently in the UCL in previous seasons, due to their inconsistent performance which forced the two of them to fight on the ECL stage.

Apart from Manchester United and Barcelona, there are other big teams like Juventus, Arsenal, Ajax and several other big teams who are ready to give competition in the ECL this season. If the big teams make it to the quarter-finals, this season's ECL feels like UCL. The final will also be more exciting when compared to the last few seasons.

It's fine if Ronaldo wants to criticize Manchester United, but the way he does it is unacceptable to Manchester United. In the interview, Ronaldo attacked Manchester United head on, he expressed his frustration at a number of names in control at Manchester United including Ten Hag.

Ronaldo conflict with Manchester United is no longer peaceful, Manchester United does not want Ronaldo to be at Old Trafford any longer. Manchester United have removed the giant Ronaldo poster that was installed at Old Trafford Stadium. The poster's removal sparked speculation that Ronaldo career at Manchester United was over.
The existence of Ronaldo in the Manchester United Squad also did not really help the club, he sat more on the bench than playing in the main squad, Ronaldo's departure can also save the club's expenses.

Percentage of wins for Manchester United with Ronaldo and without Ronaldo.

No, Xavi is not leaving Barcelona and the club will not allow that to happen. Trust in Xavi is still very high, Barcelona still has the chance to win La Liga and UEL. Xavi needed time to rebuild the Barcelona squad, economic difficulties hampered Xavi's work a bit but he was able to persuade Laporta to bring in several players in the last transfer market.

Slowly Barcelona performance has improved under Xavi direction, after a very long wait they have managed to return to first place.
Barcelona needs additional income to balance income with expenses, winning several titles can lighten Barcelona burden. The world cup could also work in Barcelona's favour, if a player gets knocked out in the group stage his club will receive €180k. Reaching the round of 16 will be awarded €220k, Qfs €280k and the Final €370k. Barcelona will benefit greatly if Spain makes it to the final.

Union Berlin which has been at the top of the Bundesliga for almost two months, has now fallen to fifth place with 27 points after its performance has declined in the last few games. Initially, many believed that Union Berlin would be able to display the slick game they had shown since the start of the season, so many placed bets on their victory. Their hopes were dashed after Union Berlin performance dropped and it was very easy to lose.

Union Berlin slowly began to decline in the standings list, Union Berlin slick progress turned out to only last temporarily, now they are out of the Champions League Zone. Betting on a team like Union Berlin is very risky, the winning streak that was obtained at the start of the season was just luck. It's better to skip betting on a team that can't keep up its form. After being beaten by Leverkusen with a heavy score (5-0), Union Berlin is no longer on my list.

All the Napoli players who have joined the main squad have very good connections, they are able to give the best performances that have made Napoli succeed at the top of the standings. The break slightly affected Napoli appearance, but it won't make their performance decrease. To reconnect with each other after the break requires a game or two.

Spalletti will not be too worried about the players performance after the break, he is very afraid that his flagship player will get injured while defending his country. Spalletti can add hours of practice to allow players to maintain their performance, Napoli is also not too pressured because of the distance with Milan, who are in second place 8 points adrift.

It was not difficult for Spalletti to bring his squad back to their best form. What needs to be worried about when the break is over is that his flagship player is injured, this will greatly affect Napoli appearance in the upcoming matches.

The problem Barcelona is facing is not the quality of the players or their poor performance, this season Barcelona has performed well after bringing in several experienced players. The arrival of Kounde has made Barcelona's defense stronger, Kounde immediately adapted well and was able to partner perfectly with Araujo.

Improving Balde performance has also benefited Barcelona. This Wonderkid who graduated from La Masia always looks good when given minutes to play. Apart from having made it into the main squad, he is also able to play in two sectors at the same time as left back and right back.

The three midfielders who are always filled with talented young players have made many changes in Barcelona form of play, De Jong, Pedri and Gavi have made Barcelona midfield more solid and able to control the game well.
There is no need to doubt the attack line filled with Lewandowski, Barcelona could easily have looked for the winning goal when Lewandowski got the ball.

Barcelona only weakness this season is difficulty winning when facing big teams, Xavi must find the best strategy to achieve his goals this season, including being able to keep up with teams that are on par with the Barcelona squad.

Manchester City performance has always been consistent throughout their years in the EPL and they can also dominate the EPL by becoming Champions every season.
This season, Manchester City dominance has been disrupted by Arsenal, the improvement in Arsenal performance has brought Arteta team to the top position with a five point lead from Manchester City, which is one rank below.

Losing points in several matches made Manchester City lose the position it usually occupied in the previous several seasons. Even though the five-point difference from Arsenal has not put Manchester City off the championship path, Haaland and his friends can still overtake Arsenal because Man City and Arsenal have yet to meet each other in the EPL.

The results of the Man City vs Arsenal match will determine who will win the EPL this season. Arsenal, who have been waiting for this moment for a long time, will continue to struggle to maintain their position, but Man City will not allow their dominance to be disturbed, especially now that Man City has a finisher that can make Arsenal dreams fall apart.

The success and failure of a team to win the Champions League trophy is not due to having many star players in their squad. I prefer to say a team that wins a trophy is a team that is able to work together well and don't panic easily when their position is under pressure.

PSG and Manchester City have always been on the list of favourites, but in reality these two teams have yet to win the UCL title.
The weakness of PSG and Manchester City is not that there are many star players in their squad, but that they are unable to control their emotions when they are in a pressured position, which makes their entire plan fall apart.

When they won the UCL trophy, almost the entire Real Madrid squad was filled with star players, from goalkeepers to strikers. So to become a champion, it is not only necessary to have the strength of a team, the mentality and enthusiasm of the players are also a factor in the success of a team.

Ronaldo and Messi are very often talked about at the 2022 World Cup because this is the last time for the two football legends to play in the highest tournament. His age is no longer young, making fans hope that one of these two players can get a World Cup trophy before retiring from the national team.

The world cup is not about Ronaldo and Messi, there are still many other star players from various countries who want to help their country won the most prestigious tournament.
All teams will fight to be the best. If I may say so, I really hope that Portugal and Argentina will go to the final. Ronaldo and Messi will face each other to be the best at the end of their careers and will be the most beautiful story when they hang up their boots.

The Champions League title has always eluded PSG, since forming its squad with world-class star players, PSG has not been able to win the most prestigious trophy in Europe. This time PSG will face Bayern Munich, in theory the squads of the two teams are almost equally strong. But mentally, Bayern Munich is superior to PSG.

After being defeated by Real Madrid last season, PSG will be reunited with a strong team capable of winning all matches in the group stage. PSG only hope in order to go further in the UCL must overcome the obstacles of Bayern Munich, PSG must be optimistic and can apply the form of the game as shown in Ligue 1. Bayern Munich can still be beaten as long as Neymar, Messi and Mbappe can do something to surprise Munich, only goals can make PSG continue to win while bringing them closer to the Trophy.

Where do you judge Barcelona having problems with its defense.
Barcelona has the best defense in Europe's top five leagues. So far, only 5 goals have been conceded in La Liga. Xavi will try to get past the hurdles of Manchester United, Barcelona must be optimistic that their strength will be able to go further, including making Manchester United come home early in the Europa League.

The Barcelona midfielder is also very good, Xavi has some young talent who are playing quite well in the midfield position. The combination of Pedri, Gavi and De Jong made Barcelona's midfield very cohesive and able to liven up the game. There is no need to doubt Barcelona's attack line, all the players in the striker and winger positions are star players.
Overall I don't doubt Barcelona current squad, only Xavi can determine Barcelona direction in the Europa League. He must always approach players to give personal direction in order to maintain his performance, especially when dealing with big teams.

Only player injuries can put Napoli in a difficult position, Spalletti really hopes that all his players called up to the national team do not experience any problems. Napoli have managed to make other teams jealous with their performances, their pace is very fast. When the other team was refueling, Napoli even stepped on the gas as if the fuel never ran out.

The break has provided many benefits for Juventus, during the break Juventus hopes that some of its pillar players can recover when the World Cup is over. Juventus which is in the best condition due to winning the last six matches, can rest for a while while doing light training with players who are not included in the national team squad.
Allegri who was rumored to be sacked soon, has won the trust of Juventus officials again, he will be given a minimum of time after the season is over. If Allegri is able to help Juventus finish in the champions league zone, he still deserves to be given a chance for next year.

Arsenal has passed several obstacles from big clubs perfectly, Arsenal only defeat from a big club was when they were beaten by Manchester United. There is no reason for Arsenal to relax, retaining the top spot month of easy work. Manchester City continues to catch up with Arsenal, the difference of 5 points is not something that is difficult for Manchester City catch Arsenal.
Only consistent performance can keep Arsenal at the top of the standings, Arteta will not waste the opportunity to win the EPL title this season. He will fight to give Arsenal the EPL title that has not been won for a long time.

This season has been very beautiful for Arsenal, after failing to finish in the top four last season Arsenal have overhauled their team in the transfer market. Arsenal squad depth has improved a lot from before, Arteta will try to bring in a few more players in the January transfer window to add to Arsenal strength for the title at the end of the season.

I don't think Barcelona will take firm action against Xavi, the failure in the Champions League is not a reason for Barcelona to end their partnership with Xavi. It should be underlined, there is no perfect coach, failure must be obtained at certain times. The club must not act rashly, Xavi still deserves to be retained as coach because he has succeeded in bringing Barcelona to the top of the table in La Liga.

Rebuilding a team that has fallen apart is not an easy matter, it takes time for any coach to rearrange it into a frightening squad. Xavi is building Barcelona slowly, what Xavi needs now is time and support from all management to bring Barcelona back to the top of glory. I think Xavi is able to bring back the glory of Barcelona because he uses the same philosophy as Pep Guardiola.

Lens has made a surprise with impressive performances this season, five points clear of PSG who are in first place is a very good achievement made by Lens. PSG, which always dominates Ligue 1, is very difficult to be disturbed by a team like Lens, PSG always gives the best performance in Ligue 1 with the strength they have. The PSG squad is still unmatched in Ligue 1, Lens is only able to sit in second place, if for the first place it is very difficult to do.

Competition in Ligue 1 is only limited to chasing points, if for the champion only PSG are able to achieve it. Ligue 1 is the same as the Bundesliga, whoever sits in first place during the season is still rolling, Only PSG will win the trophy. Due to a lack of competition in the domestic league and lack of consistency on the European stage, PSG has always had difficulty getting the Champions League trophy.

The chance is still there, but it's very slim, this season there are several teams that have managed to add to the competition in the top four positions. Arsenal and Newcastle have enlivened the competition with impressive performances shown since the start of the season, Arsenal managed to sit in first place by breaking the dominance of Manchester City. Meanwhile, Newcastle have appeared extraordinary this season which has made them successful in third place.

Tottenham, Manchester United, Liverpool and Brighton are above Chelsea, there is still a lot for Chelsea to do to get into the top four. Potter has not been able to fulfill the hopes of Chelsea's owners, defeats in the last few matches have made Chelsea slump to eighth place. It took a consistent struggle for Chelsea to get past several teams that were above it, with the more teams that occupy the top four positions the less chance Chelsea have to re-enter the UCL zone.

Ronaldo and Messi are two of the best players ever, I'm very lucky to be able to enjoy them live. The 2022 world cup will be the last for both of them, the world cup trophy being the only one Ronaldo and Messi have never won.
Everyone will expect these two players to fight to bring their country to world cup champions, the final will be more interesting if they fight each other to be the best.

If Portugal and Argentina manage to qualify for the final, my assumption is that Argentina will win because Argentina head into the world cup unbeaten in the 35 games. But something sad could have happened in the final because the atmosphere was very challenging, Portugal could have stolen the opportunity when the Argentine players were off guard at several points.

Real Madrid is not a match for Liverpool at the moment, the hopes of the fans will be in vain if Klopp is unable to revive the quality of Liverpool game. Real Madrid has always been able to maintain its performance, after having success last season, Real Madrid appearance has not changed one bit this season. While Liverpool's performances are still up and down, it is very difficult to predict, sometimes they win with big scores and sometimes they lose to small clubs.

Liverpool wounds are still imprinted when defeated by Real Madrid last season, this season Liverpool are reunited with a team that always makes Liverpool hopes dashed. A mature strategy must be prepared by Klopp to face a team like Real Madrid, the back line is one that needs attention.