Former Arsenal manager Arsene Wenger believes the decision to offer Mesut Ozil a long-term contract last year may have left the German in a "comfort zone".
Ozil ended speculation about his future last year by committing himself to the Gunners until the summer of 2021, with Wenger still at the helm.
But Ozil has fallen out of favour under Wenger's successor Unai Emery, having started just one game since Boxing Day to once more bring scrutiny as to whether he will remain at the Emirates Stadium.
Wenger, speaking after being honoured with the Lifetime Achievement Award at the Laureus World Sports Awards, said: "I feel that the length of the contract has nothing to do normally with the selection of the team. But sometimes there are special cases.
"Most of the time now we think when we sign a player for five years we have a good player for five years. But that doesn't necessarily mean that they practice, they play their best. Because they might be in their comfort zone.
"He has a contract but the problem is that if you want to buy a player like him you have to spend £100million.
"And to maintain the value of the player, beyond the Ozil case, it is more about the way football is structured.
"To buy players of top, top quality you need £100million. So the decision you have to make is whether you re-sign the player, who costs us nothing, or do we have the money to buy a new player?"