Wigan Athletic left-back Maynor Figueroa is facing a lengthy spell out of action after suffering knee ligament damage in the 3-1 victory at Burnley.
The 26-year-old Honduras defender was injured early on at Turf Moor, but managed to last almost half-an-hour before being forced to limp off.
Subsequent tests have shown ligament damage in his left knee and manager Roberto Martinez is fearing the worst.
He told the Evening Post: "Maynor has a grade two medial ligament problem in his left knee. We will assess it further to see how bad he is, but it doesn't look too good.
"Normally, with this sort of injury, you are talking about weeks rather than months, but the signs are not nice.
"He actually wanted to carry on, but the injury was serious and he couldn't do so.
"It's not an injury that he would have damaged any further as it was just a tear, it's muscle problems that can get worse, but Maynor felt so uncomfortable that he had to come off."