He is, however, delighted to have both men on his books at present and is tipping them to earn England recognition.
Forster has already figured in Roy Hodgson's international plans, while Hooper's prolific form has sparked calls for him to be given a chance.
Lennon does not believe that playing in the Scottish Premier League will hold either man back, but appreciates that the day will come when suitable offers for the pair are tabled.
As he readies his troops for a UEFA Champions League clash with Juventus on Tuesday, Lennon told The Sun: "It is a back-handed compliment to have scouts at your stadium.
"Every player has a price and we will have to sell eventually. Then you have to start again.
"Fraser is excellent. In my opinion, he is England's best keeper after Joe Hart - although I am biased. Gary is good enough to be in the England squad.
"I think Roy Hodgson will come up and watch the two of them on Tuesday. Credit to Roy as he is prepared to do that. Some managers would shut the door on the SPL, but the Champions League has been so important for those two guys.
"To get two players in the England squad would be fantastic."
While Forster and Hooper have been strongly linked with moves back to English football, Lennon has also been touted as a potential Premier League boss.
He is, however, enjoying his role at Parkhead and has no intention of ending an association with Celtic which has seen him spend 12 years in Glasgow as a player and coach.
Asked about his future, Lennon said: "I am on a rolling contract and have a great relationship with the club's chief executive and the board.
"I loved my time in England but I have been here 12 years and what this club gives you is the chance to manage in the Champions League."