The Royals have turned down a bid from the Owls for the winger, who was on loan at Hillsborough last season, but McDermott has revealed that a deal could be done if they return with a more acceptable offer.
"There's been an offer, but we've turned it down," McDermott said. "I'm not sure how much we have heard since.
"Michail's view is that there are a lot of players in front of him, so he needs to move on for his career. That's absolutely fine and I understand that.
"He's training well and working well. We love Michail, so we will see what happens.
"He's in a great environment here working with some really good players and he's always trying to be the best that he possibly can."