Stuart Holden is expected to be sidelined for up to six months after it was confirmed he has damaged ligaments in his knee.
The Bolton midfielder was injured in a horror challenge by Manchester United's Jonny Evans at Old Trafford on Saturday which got the Northern Irishman sent off with just over 20 minutes remaining.
Trotters boss Owen Coyle said that the USA international will now spend up to half a year recovering.
"First and foremost our main concern is for Stuart and his recovery. He will get all the time and support that he needs," he told the club's official website.
"Stuart has been outstanding for me this season and he has shown in his performances that he is one of the best midfielders in the Barclays Premier League.
"He has such desire, strength of character and a winning mentality, and he will draw on those attributes in his rehabilitation."
Despite sustaining such a serious injury, Holden said he held no grudges toward Evans for the tackle.
"Just had a sincere phone call from Jonny Evans wishing me the best in my recovery, def wasn't intentional, just unfortunate part of the game," he posted on his Twitter page.
