Ukraine captain Andriy Shevchenko has injured his left knee and is a doubt for his team's must-win match against England on Tuesday in Group D of the European Championship.
Team spokesman Oleksandr Glyvynskiy said the striker's knee was swollen after picking up knocks in the previous group games against Sweden and France.
"We hope he can play but for the moment he is doubtful for the match," Glyvynskiy said.
Team doctor Leonid Mironov told a local TV station that the medical staff was working with Shevchenko in order to get him fit in time for Tuesday.
According to Mironov, such an injury would normally require two or three days of rest.
Shevchenko, who scored both his team's goals in an opening 2-1 win over Sweden, missed training on Sunday because of the injury.
Ukraine need to beat England to stand a chance of advancing to the quarterfinals and missing Shevchenko would be a massive blow.
"He is a bit injured," Ukraine teammate Anatoliy Tymoshchuk said. "I don't think it is that bad. He is a very important player for us so let's hope he can play. He's our top scorer so it would be a shame if he can't play."
Shevchenko is ending his international career after Euro 2012.