Bolton Wanderers manager Dougie Freedman has revealed that the club are awaiting results on Stuart Holden's "disappointing" injury setback.
The USA international lasted just 23 minutes in an Under-21s match against Everton on Monday when he pulled up and was forced off the field.
It was the first time that Holden had played in a match since a seven-month layoff with cruciate ligament damage.
"It's disappointing news for us all," Freedman told the club's official website. "We don't know the exact results at the moment, but we feel that it's the same injury. He's since had his scans and he's going to fly back to America to see his specialist on Monday.
"Hopefully he can read his scans and tell us good news, but if not he will need to go into the knee and have a look at it. I did go and meet Stuart the following night to have a long chat with him – he's very positive and no matter what the outcome of this is, he will carry on and keep on going.
"I want to be very clear to everybody that Stuart Holden will be here in some capacity at this football club. He is such a fantastic lad and is a great ambassador for this football club."
Holden last featured in Bolton's first team on January 26 last year during an FA Cup tie against Everton.