The Finland international striker bagged his first ever treble in this country during the 4-1 demolition of Spurs at St Andrew's on Saturday.
"I'm really pleased for Mikael. I've had him in and out of the team since I came here, but the lack of goals in previous weeks meant I had to push his experience back into the team," McLeish said.
"He was merciless in front of goal. He could have had four or five goals, but his link-up play was also good. He had a terrific game."
"He's had a lot of injury problems and when they are of that magnitude, it is going to have some effect.
"It is a case of whether he can play 40 games a season, but when he is as hot as that, we have to wrap him in cotton wool."