The Irishman has led the Hoops to the past two SPL titles but Dutchman Petta is confident he will only stay at Parkhead provided an offer from a top flight English club doesn't come along.
"I'm not surprised there is interest because Neil has done extremely well in his three years as a manager. He didn't have much experience before this post and it's a tough job.
"The Premier League is better and it's where the money is. The cameras are focused on Spain, Germany and England.
"It would have to be a very good offer to make Lenny leave Celtic. His heart is here.
"If you are made a very good offer, you have to consider it but at this moment in time there isn't any reason for him to go."