Derek Ferguson has told Danny Rohl why he should drop Andreas Skov Olsen as Rangers play host to Celtic this Sunday.
Skov Olsen moved to Ibrox in the January transfer window from VFL Wolfsburg, with an option to buy for £8m.
Rohl has handed the Denmark international six appearances thus far, and he has a return of one goal and one assist.

Derek Ferguson believes Mohammed Diomande should start for Rangers vs Celtic
Ferguson admits that he has not been pleased with Skov Olsen since his January move to Rangers.
While it has only been one full month since he moved to Glasgow, his performances have not impressed the former Gers midfielder.
In his view, the 26-year-old has not done or shown enough to start in one of the most important games of the season.

Rohl has played a 4-2-2-2 in recent weeks, and that brought him success, particularly against Hearts, with Rangers winning 4-2.
However, Ferguson believes the German should ditch that system and revert to a three-man midfield with Mohamed Diomande coming in for Skov Olsen.
He told Open Goal: “I’d bring Diomande back in there. I’m not going with Skov Olsen. I don’t think he’s done enough, shown enough. I’m going with the three in midfield.”

What the underlying numbers say about Andreas Skov Olsen
Skov Olsen has made five league appearances and has managed to find the back of the net just once.
In terms of his creativity, the returns are mediocre as well.
Per Sofascore, he has provided just one assist, an xA of 0.85, and has created just three big chances.
The main reason for his joining was to offer creativity from the number 10 and wing areas.
The Dane also has a goal conversion rate of 20 per cent – something which he will need to improve on if he is to start regularly.
His cross accuracy of 26 per cent has also been underwhelming, as he has not even able to be a threat when deployed as a winger.
Rohl does have a big call to make, but he also may not want to tweak what he thinks is his best eleven, so the likelihood of Skov Olsen starting against Celtic is pretty high.
