Australian midfielder Tom Rogic has not played for Celtic since 2013.
Rogic has not played for the Bhoys all season, with injury hampering his progress, but the midfielder is stepping up his road to recovery now.
The Australia international played 60 minutes for the club's development side in the week without suffering any discomfort, and Frail has been speaking highly of his ability.
The Celtic academy coach says that the club's youngsters have been learning from Rogic during his time training with them and has backed the 22-year-old to break into Ronny Deila's senior plans before the 2014/15 campaign comes to a close.
He said: “His road to recovery has been a long, lonely road for him. He’s enjoying playing for the team as he has hasn’t played for so long. He’s a great addition to the side. The players see how he uses his strength and body.
“He’s maybe not the quickest player over the ground, but upstairs he knows how to see the game and he reads it very well. He uses his strength well and can pass it.
“I’m really pleased he got a goal as well. He got another 60 minutes in his comeback and he will need a few more games and then hopefully he can feature in the first team before the end of the season.”
There are big expectations for Rogic at Parkhead and the hope will be that his lengthy spells on the sidelines have not impacted on his ability too heavily.
The 22-year-old appears to be one of the brighter talents at the club, despite his struggles for game time, but he will need to stay off the treatment table from now on if he is to fulfil his potential.
So far Rogic has made 15 appearances for Celtic, but he has not been seen since November 2013, when he played against AC Milan in the Champions League.