The England Under-21 international suffered the injury in the 3-1 home defeat to Fulham on Saturday.
Trotters boss Gary Megson told the club’s official website: “Mark is struggling. We don’t know exactly how long it will be for but we’d consider it long term.
“We hope he will be back before the end of the season. This kind of thing happens, but he will get over it because he’s a young lad.”