Sima has scored in four successive matches for Rangers and has a total of seven goals in all competitions this season.
The 22-year-old forward has come to the fore in a Rangers team who have struggled for any sort of consistency this season.
McCann feels his performance levels have not matched his goal return so far but conceded that it must be unsettling for him to get constantly shifted around in the forward line.
He believes Sima needs a settled position in the starting eleven but admitted that given Rangers’ current form, the forward should be more than happy about the way he has started at Ibrox.
The former Rangers star said on BBC Radio Scotland: “He has scored goals but his performances at times haven’t glowed.
“But he has moved from right to left, he has gone centre-forward – I don’t think there is a position for him nailed down where he is a certain starter in that position and that might be unsettling for him.
“He has got attributes that are absolutely there to be an impactful player for Rangers.
“His pace and power and I would love to see him steady himself, get it under control and go.
“Without question when you look where they are and where he is now at the start of his Rangers career that’s not a bad return, considering how poorly Rangers have been playing.”
It remains to be seen whether Sima can convince the new Rangers boss whenever he is appointed to get a settled position in the team.
