Lyon boss Claude Puel has admitted he is worried by the length of time it is taking Lisandro Lopez to recover from an Achilles injury.
The Argentine striker, who joined Lyon from Porto 12 months ago, has been out of action since picking up the injury in pre-season at the start of July.
He was not initially expected to be sidelined for too long but the road back to fitness has been slow and Puel is not sure when the 27-year-old will be ready to play.
"It's pretty much up to him to decide when he returns," said Puel.
"In the MRI scan, there's a little mark on the sheath of his tendon. It depends on how the player feels.
"It worries me a little bit because I was expecting him to be able to return more quickly and at the start, it wasn't a serious injury."
Lyon have picked up just one point from their opening two Ligue 1 games of the season and Puel is keen to have Lisandro available again as quickly as possible.
"He's spent a month and a half doing nothing, to which you have to add a month and a half of holidays during which he didn't do anything either," explained the manager.
"That makes a total of three months. He wants to get back. He's had enough.
"A player who isn't on the pitch always finds it hard. He's not good at the moment."
Puel also hit back over the one-match international ban given to midfielder Jeremy Toulalan for his role in the France squad's training boycott at the World Cup.
"It's a match too much," said Puel. "There's not much objectivity in this punishment.
"The players have already been punished enough in terms of what happened during the World Cup and afterwards."