Blackburn midfielder Bradley Dack faces 12 months out after suffering an anterior cruciate knee ligament injury in Monday's goalless draw with Wigan.
Rovers' 25-year-old 10-goal top scorer was injured in a challenge with Sam Morsy and carried off on a stretcher following a lengthy delay.
Boss Tony Mowbray told BBC Radio Lancashire that Dack would have an operation early in the new year.
"We'll see him probably this time next year," he said.
Blackburn were held to a 1-1 draw by Birmingham City at Ewood Park on Boxing Day in their first game since Dack's injury, leaving them just outside the Championship play-off places.
"It's a big blow for Bradley, first and foremost," said Mowbray after the draw with Blues, which extended their unbeaten run to eight games.
"For the club it's hugely disappointing and maybe on a day like today Bradley Dack can do something on the pitch that takes the mediocrity out of it.
"We're here to support him and he'll come back stronger I'm sure. We will do our best in the period he's out and unavailable to us."
Despite the January transfer window opening next week, Mowbray challenged the other attacking players within his squad to make the most of the opportunity presented by Dack's absence.
"We're not sitting here with loads of cash to go and buy another big-name number 10," he added.
"If someone leaves and we can create some space in the budget then we might sign, but if not then the likes of [Lewis] Holtby, [Joe] Rothwell, [John] Buckley, [Ben] Brereton and [Dominic] Samuel have to step up to try to help us score goals."