Gray told The Herald: "He's a no-nonsense centre-half and has been captain of the reserves for the last year and a half.
"It will be good to see how he does. I'm sure he will do really well at this level."
He also made five starts for Peterborough United while on loan to the then League One club at the end of last season.
Asked whether Chester could make a similar impact to Craig Cathcart at Argyle, Gray replied: "I don't see why not.
"He played in the Carling Cup last season, so the fact the manager (Sir Alex Ferguson) gave him a chance shows he has got a bit about him.
"I think this is the next step he needs."