Manchester City forward Raheem Sterling might not play again this season after picking up a groin injury in the Manchester derby, a source told ESPN FC.
The 21-year-old is set miss six to eight weeks after hobbling out of Sunday's 1-0 defeat to Manchester United in the 26th minute at the Etihad.
If Sterling is ruled out for the full eight weeks, he would miss the final day of the Premier League, which is on May 15, although he would be back in time for the Champions League final on May 28 if City should qualify.
Sterling is also in a race to prove his fitness in time for Euro 2016, with England manager Roy Hodgson set to name his 23-man squad on May 12.
There is better news about Joe Hart, however, with the City keeper set to return from a calf injury sooner than expected.
City boss Manuel Pellegrini initially ruled the England keeper out for a month after he left the pitch against United on a stretcher.
However, Hart could be back in just two weeks after scans revealed the damage wasn't as bad as feared.
He pulled out of the England squad for the friendlies with Germany and Netherlands this week, but could return for City's Premier League game with Bournemouth on April 2, or the Champions League quarterfinal first leg against Paris Saint-Germain on April 6.