Roberts joined Scottish Premiership giants Celtic on loan from Premier League outfit Manchester City in the January transfer window.
The 19-year-old winger has been playing well for the Bhoys so far and has impressed the Celtic Park faithful.
The former Fulham youngster featured for Celtic against Old Firm rivals Rangers in the semi-finals of the Scottish Cup at Hampden Park in Glasgow last weekend.
Brazil, who is a Celtic fan, believes that Roberts needs to mix it up on the wing and make himself more difficult to defend against.
“The young boy Roberts for Celtic, smashing little player, comes inside on his left foot every time,” said the former Scotland international on the Alan Brazil Upfront podcast on Audioboom while discussing his performance against Rangers. “You have to go outside to come inside, you go inside, then go outside.”
Celtic, who lost the game to Rangers on penalties, will return to action this afternoon when they take on Ross County at home in the Scottish Premiership.
Ronny Deila’s side are at the top of the league table at the moment with 76 points from 33 matches, eight points clear of second-placed Aberdeen, who have a game in hand.