Wigan midfielder Ben Watson may require surgery after breaking his leg in a freak collision during the 3-0 defeat to Liverpool at Anfield.
The 27-year-old was caught just above the shin by Reds winger Raheem Sterling's knee as they jumped for a ball in the first half.
Watson required several minutes of treatment but declined the stretcher and hobbled off, assisted by two members of the Wigan medical staff.
Despite further attention down by the touchline the midfielder struggled to put any weight on his right leg and was eventually taken down the tunnel.
"It is a broken leg and we are going to miss him," said manager Roberto Martinez.
"He has a fracture and we are going to assess him now because maybe he will require surgery.
"We will see what the extent of the breakage is and what treatment he needs.
"We are really disappointed because he was at a good level."
Martinez added: "It is very serious. We need to see what the specialist says because if we need surgery it could be really difficult.
"We will keep our fingers crossed we can treat the breakage in a more conservative way.
"If he needs surgery he will probably be out for four months and that will be a major blow for us."