Ibrahimovic sustained a serious knee injury in the quarterfinal Europa League win over Anderlecht, and is believed to be out for the season. However, no official statement has been released by the club.
Burnley host United at Turf Moor on Sunday and Dyche is backing Rooney to step up for the Swede.
“They’re not short of options, without a shadow of a doubt,” Dyche told reporters.
“The one everyone thinks is not that good anymore, I think he’s decent – the boy Rooney, I always think he ain’t bad. I certainly think if they chose to play him, I don’t think he would let anyone down.
“You get to an age where you’re questioned regardless of performances. He’s a top-class player; you can’t achieve what he’s achieved in the game and not be a top-class player. You can’t cheat the system. Whatever his journey forward is he will remain a top-class player in my eyes.”