The midfielder joined on a season-long loan from Angers in mid-July.
His story of the so far, is really one of two parts.
In the first, he was excellent.
In his initial four or five outings in a Rangers shirt, he really looked the part.
A big physical presence, he instantly became a destroyer type figure in centre of the park.
However, that roaring start was disrupted by an untimely injury. The problem kept him out for around three weeks and seemed to have a profound impact upon his confidence.
Since then, he simply hasn’t been the same player.
The Mali international still puts himself about, but he has had decreasing impact on matches.
Of course, in December, he wasn’t helped by being asked to play an unfamiliar position. In the absence of Scott Arfield and Ryan Kent, he was asked to move forward to support Alfredo Morelos.
That role simply doesn’t suit his strengths.
It’s fair to say that the winter break came at a good time for Coulibaly. Despite his early injury, he has played 25 matches so far, which is a considerable workload.
The time off will have given a chance to recharge and come back ready to prove his worth.
At only 22, it’s unfair to expect the finished article.
However, he has expressed a desire stay at Rangers, and for him to get that opportunity, he must improve.
If he can hit the heights he reached at the very beginning of the season, it could have as big an impact as a new signing.