Former Rangers coach lifts lid on 'disruptive' Nico Raskin - but insists Russell Martin is making a mistake

McCann was part of the interim coaching team that took charge of Rangers until the end of last season following the sacking of Philippe Clement in February, working under Barry Ferguson.

The ex-Rangers winger admitted that his own relationship with Raskin had been strained at times, revealing he became involved in a "very heated exchange" with the Belgium internationalist after he questioned tactics.

However, McCann explained that he and his fellow coaches were able to smooth things over with Raskin and the team felt the benefits with the 24-year-old producing some eye-catching displays.

Martin's relationship with Raskin appears to have broken down though after the former Standard Liege midfielder was excluded from the Rangers matchday squad for the goalless draw with Celtic at Ibrox amid suggestions he could now depart the club before Monday's transfer deadline.

McCann believes that would be the wrong decision.

"If there's a problem, I think sit down with Nico and try to smooth it out," McCann said on Sky Sports. "If he's been disruptive in the dressing room that's something the players have got to deal with as well, not just the manager.

"The disruptive nature of Nico came from him challenging us last season on the training field. Whether you were going through shape towards a game, he would question you. I had a very heated exchanged with him regarding how we wanted him to play as a left-sided eight and he was coming in to where Connor Barron was. I was saying, 'you're actually disrupting how we want to play'. I showed him five or six examples and he took it on board. He still had something to say, 'well I can come in and start things', and you have to be strong with him. But you have to understand that once it seeps into him, and he gets it, he generally accepted it last year.

"I actualy thought he was brilliant when we were in there. He went on and starred for Belgium, he scored against Celtic, he bossed a lot of games, he was brilliant in the European games. So I would've loved Russell to sit down and say, 'maybe I'm making a mistake here'."

McCann also feels Raskin's transfer value has been diminished by the current state of affairs.

"I feel this situation should have been resolved to keep Rangers' biggest sellable asset in the building," he said. "Allow him to recapture the form that Russell said the team is going to get, let him recapture that power that got him into the Belgium team and the reputatoin he was starting to build, and then sell him come January as a top asset.

"But just now his value has diminished because of his performances, yes, but also all of this bad power that's going about the ground and the questions being asked about him. He's going to walk out of this place, it looks like, and Rangers are going to lose out.

“Generally, someone who is starting for Belgium is £20million and upwards. Of course, he's got to perform at Rangers and do the things that I believe he can do, and then go away and perform with Belgium. If he's doing that, that is an unbelievable asset in here. To allow him to leave, and look at that asset maybe going on loan with an obligation or a possibility of buying, or a far reduced value, I think is a real shame not only for the club but for Russell and Rangers as a team because I think he's a quality operator.”