Gray is excited at the prospect of Mirallas terrifying defences up and down the country under new manager Roberto Martinez's guidance.
"Kevin Mirallas got six league goals and I thought he finished the season really well," Gray explained to evertonfc.com. "I'm really excited by seeing how he will start because he gave a snap-shot of how good he might be.
"What I was impressed with was that when he got his chance he took it, so much so that David [Moyes] had to play him. He ended up starting over 25 games so that's a measure of how important he was to Everton.
"I think Kevin could be one of the really big stars next season if he has a good pre-season and everything goes well for him. He has got that little bit of magic and can do things with a football that not every Everton player can.
"He can play in the wide areas of the pitch where he can run at people, he can play off the frontman and if you get him in the middle of the pitch in real dangerous areas he can cause problems.
"I think it will be interesting to see what area of the pitch Roberto plays him in."