United States head coach Jurgen Klinsmann believes Bolton's American midfielder Stuart Holden may have suffered a "very serious" knee injury during his country's Gold Cup win against Panama.
Holden has been plagued by trouble with the same right knee in the past, missing almost two years of football after sustaining a major injury against Manchester United in 2011.
He went down hurt in the 18th minute of the Gold Cup final last night and was substituted by Klinsmann.
Klinsmann said: "We are very concerned about Stuart's situation.
"It looks like a very serious injury, but I'm not a doctor and I can't confirm it."
Former Germany striker Klinsmann added on ussoccer.com: "We'll get an MRI and he'll have all the tests done. Stu is a player that when something happens, he knows when something happens. Hopefully it's not as bad, but it's not looking good right now."
Holden wrote on Twitter after the match: "For all that know me + have supported me, I hope u know I will always prevail no matter what the outcome. Fingers crossed. Let's celebrate!"