McDermott told talkSPORT: "There's lots of interest from the Premier League as you can imagine, because he's a top player.
"Shane Long's going to get better and better. He's not only a top player but a top person.
"The way things are going, my experience is that we've had interest from lots of clubs in the Premier League and once someone makes a bid then four or five will make a bid."
McDermott also reiterated that despite the interest in his star man he would still prefer not to sell Long at all.
"He's not a player that I would want to leave the club because he is very important," he added.
"But if the right club comes in and agrees a deal from the Premier League then I'm sure that he may move on."