Heskey had only a bit-part role to play during the second half of last season following the arrival of club-record signing Darren Bent in January.
The 33-year-old was linked with a move to his first club, Leicester, during the summer but McLeish is happy to retain the services of the former England player, who is in the final year of his current contract.
McLeish said: "Emile's experience is phenomenal. He has enormous experience.
"He has played for England, he has played for several top managers over the years so he has learnt a lot.
"Discarding his kind of knowledge and his skills would be crazy. I have to tap into a guy like that. I have to use him to the full.
"There is no guarantee that Emile will play every week - but he has certainly impressed me."
Heskey regained his spot initially after Gerard Houllier's arrival as manager last season but Bent's ?18million capture saw him revert to being a back-up player.
Source: Team Talk
Source: Team Talk