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.

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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.

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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...