If Robin Van Persie were to leave Arsenal this summer, fans of the London club would be distraught.
After losing both Cesc Fabregas and Samir Nasri last season, Arsenal has gone through another disappointing campaign which could lead to the Dutch forward's departure.
Van Persie's future at Arsenal has been the subject of much speculation with his great form for Arsenal leading to much attention from some of the big clubs across Europe.
He is not the only player whose departure would have a significant effect on the club's supporters, though. This list looks at players who are likely to leave their club, for whatever reason.
As that is the case, there are no major players from Barcelona, nor a certain No. 7 from Real Madrid. If players like Lionel Messi, Andres Iniesta or Cristiano Ronaldo were to leave either club, it would be devastating, but those transfers are almost impossibilities.
Read on to find 15 players who would break their fans' hearts if they left their club.
Robin Van Persie took over the captaincy of Arsenal and has led the team and the forward line with great effectiveness this season.
His goal-scoring output, and the general lack of output of some of his teammates, has led to some labeling Arsenal as a one-man team.
If he was to leave the club, there might not be too much problem in replacing the leadership with players like Thomas Vermaelen around, but fans would definitely be worried about where the goals would come from.
Van Persie's departure would also be another blow against the club's reputation, as they would have failed to keep their three biggest stars over the last two years.
It's safe to say that Mario Gotze is the face of Borussia Dortmund's recent resurgence in German and European football.
This starlet is one of the most sought-after players in World Football, but he has quieted a lot of talk with his commitment to his club. If Gotze is tempted to leave anytime in the near future, meaning this summer or next, it would be a blow for the club.
Gotze has the talent to be Germany's leading man for years to come, and Dortmund fans will hope that he stays in the place where it all began.
This was a close one between Luka Modric and Gareth Bale, but the Croatian playmaker wins out.
It would be hard for Tottenham to replace either player, but you feel they would be able to cope better without Bale than without Modric.
The fee that Tottenham would receive from a possible Modric sale may offset things, but it's much easier to keep a player of that caliber than to find a replacement.
Modric makes things tick for Tottenham and is a major reason why the side was so good early on this season. If they cannot keep him next season, that will decrease their chances of making a strong challenge for the title.
Some people would say Zlatan Ibrahimovic should be here, but Thiago Silva is extremely important to AC Milan.
For one piece of evidence, viewers can look at the team's away loss to Barcelona in the Champions League quarterfinal. If Thiago Silva had been available, the team would have performed much better defensively, and it could be them and not the Spanish giants facing Chelsea on Wednesday.
Another factor is the age difference between the two. Silva, at 27, is in his prime while the 30-year-old Ibrahimovic is moving towards the tail end of his career.
Silva is a future captain and current leader of the defense and would be a big, big loss for Milan.
Nemanja Vidic was a close second in this race, but what made the decision possible in the end was how United's season has gone so far this year.
Would the team have been better off with Vidic injured, as he is now, or with Wayne Rooney in his place? The defense seems to be doing fine without the Serbian, so that leaves Rooney as the winner.
United already lost one big star recently in Cristiano Ronaldo, and if Wayne Rooney were to go, fans would be worried about the state of their team.
Yes, Danny Welbeck and Javier Hernandez are waiting in the wings, but neither player can provide the same type of playing style that the club's No. 10 can.
Steven Gerrard is still Liverpool's "Captain Fantastic." He has given the club some memorable moments and despite his age and injuries over the last few years, he is still the club's main man.
Gerrard has been synonymous with Liverpool for years and that is something most people don't expect to change. He has been tempted in the past and if he were to leave the Reds, Liverpool fans would not take the news well at all.
Klaas-Jan Huntelaar has been terrific for Schalke this season after spells at Real Madrid and AC Milan, where it looked like he would not live up to his full potential.
With his ability in front of goal, Huntelaar may see himself receiving some interest from big clubs again. Fans of his current club will hope that is not the case.
Schalke could continue to build itself into regular title contenders in Germany and a regular presence in Europe with Huntelaar leading the line. If he goes, they may fall off the wagon a little.
This was another close run race between Loic Remy and Andre Ayew. Marseille's disappointing season aside, Ayew is the player that fans of the club are more likely to miss.
Ayew, from midfield, has scored just one less goal than Remy this season and was in double digits last season also.
Remy has competition in the form of Ayew's younger brother, Jordan Ayew, and is less irreplaceable to the club. Older Marseille fans may hope that Andre will stick around to try and replicate some of the success his father, Abedi Pele, had during his days at the club.
Athletic Bilbao fans have probably been holding their breath during the last few transfer windows. For all the transfer speculation, though, Fernando Llorente is still a member of the squad.
If the team can win the Europa League this year and get into the Champions League next season, chances are he will stick around.
The Basque side has produced its ample amount of talented players, but there is no ready-made replacement for a player who would play a solid role for either of Spain's two major teams.
Llorente is a world-class player in a team full of talent and with a coach that could lead them to great heights. If he remains with the team, they will have a very good chance of doing something major in the near future.
Antonio Di Natale is one of the best forwards in Europe. He is in great form this season and is the reason why Alexis Sanchez's departure has not hurt Udinese as much as expected.
While Di Natale's age, 34, may deter some suitors, if he were to leave the club for any reason, life would become more difficult for his team.
Udinese is within touching distance of returning to the Champions League qualification stages, and that's thanks to a player who has scored just under half of the team's league goals.
He has led the scoring charts for the last two seasons and is currently second to Zlatan Ibrahimovic right now.
Daniele De Rossi is second in line to Francesco Totti as Roma fans' favourite son. He has spent his whole career at the club and the club's passionate fanbase adores him.
De Rossi has been subject to transfer speculation in the past, though, and considering the fact that he has not won much silverware at the club, a good offer may tempt him.
He has been a loyal player and a constant presence in the club's midfield for years.
Olivier Giroud is firing Montpellier to a league title and a Champions League spot at the moment.
He has been linked with many clubs since the beginning of the season and if he plays a part in France's Euro 2012 campaign, and plays well, the offers could come rolling in.
If Giroud leaves after this season, he would leave the club with little chance of making an impact in Europe or retaining its title. That is provided they do finish the season as champions.
Alessandro Del Piero is the type of player who should retire at the club where he dedicated his career. He has yet to sign a new contract with Juventus.
He is on this list not because of what he could do for the club, but because of what he has done. Any Juventus fan would be unhappy to see such a legend leave and not retire as a Juventus player.
Neymar's situation at Santos will be one of the more intriguing stories for years to come. Right now, there is no indication that he will ever make a move to Europe. Especially when you look at his most recent comments.
If he does leave, Santos fans will certainly be devastated. These fans have seen new talents crop up and then depart again and again.
Neymar has been the club's product in the last few years and if he were to leave, the fans would have to wait for the next prospect, who may not bring as much success or be as good a player.
Jesus Navas has been a member of Sevilla's first team since 2003, yet he is still only 26. Thing's haven't gone well for Sevilla this season and it may be time for the player to have a change of scenery.
Navas is one of the best wingers around when on his game, but he is out of the spotlight because of the team he plays for and the dominance of two certain teams in his league.
His lengthy career and solid performances make him a fan favourite at the club and they would be entirely unhappy if he was to make a move at some point.