Tom Rogic has scored five goals in 17 appearances for Celtic this season.
McDonald, who played for Celtic between 2007 and 2010 and scored 51 times, has always considered his Australian compatriot to be a huge talent, but Rogic has made a slow start to life with the Bhoys.
The midfielder was plagued with injury for his first two seasons at Celtic, but he has transformed his form so far this term.
And McDonald said in the Glasgow Evening Times: “He is a guy who has been spoken of highly at home for a long time and I am delighted for him that he is starting to come through and show what he has got.
“He has had a really tough time with injury problems and the last two years it has been difficult for him to get anywhere near the first-team because of that.
“But he is still a young lad and it is good to see it come together for him this season. He is starting to get a run of games under Ronny Deila which will do wonders for his confidence as well as his form.
“He is at that age where he needs to be getting as many games under his belt now as possible.
“I know the lad himself has admitted that there were times when he feared it might not work out for him at Celtic but he has got himself into the first XI and it is up to him now just where he goes from here.”
Rogic has played a prominent part in Ronny Deila’s first-team for Celtic this season, and he has been very impressive.
The 22-year-old still has plenty to work on, but his power and creativity have shone through so far, and he looks to have a very exciting future ahead of him.
Rogic has scored five times in 17 appearances for the Bhoys to date, and he looks set to stay in their team for as long as he does remain fit.
Rogic’s good form has helped Celtic establish a six point lead at the top of the SPFL table, with Deila’s side’s next match coming against Kilmarnock after the international break.