Former West Ham goalkeeper Shaka Hislop does not believe his ex-teammate Paolo Di Canio is a racist, but has called on his former colleague to offer a proper explanation of his political beliefs.
Di Canio's appointment as Sunderland manager has sparked a storm of controversy given the Italian's previous statement that he is a fascist.
Sunderland and Di Canio initially declined to address the issue following his appointment, later releasing a statement in which the former Lazio player said he did not support the ideology.
But that has done little to silence the critics and the issue remains in focus as he prepares for his first game in charge today at Chelsea.
"Without any reservation I don't believe Paolo Di Canio is a racist," Hislop told BBC Radio 5 Live's Sportsweek programme.
"I say that because he's been a friend to me, not just offering me professional respect as a team-mate, but I also look at how he interacted with my wife and kids when they came around.
"I've never heard him speak any kind of political views or ever heard any hint of his thinking or ideology, not as a player."
But Hislop said he had been upset when Di Canio later moved to Lazio and gave an infamous Roman salute to the club's ultra fans.
"I have to say I was surprised and offended by it. There is no place for extreme politics or extreme ideologies in football, regardless of what your beliefs might be. If they are extreme or on the fringe of what others might be that's where you have to draw the line."
Di Canio's statement this week was not enough for Hislop, who wants to hear a proper answer from the 44-year-old who has so far declined to answer any questions about his politics.
"Fascism in its, let's say, more mild form is not seen in Italy as being all that bad or disturbing but there is still a lot of uncertainty about it as an ideology in western Europe and across the Atlantic," he said.
"This is what I'd like to hear because I'm not overly convinced by saying, 'This is a Roman salute', let's get on with it.
"I want a proper explanation because I think there's wider implications to it. As much as fascism can have a moderate side, there is an extreme element and I would like to know if Paolo falls into that category. And if he doesn't, what was his salute all about?"
Hislop, who played for Sunderland's rivals Newcastle, warned that the issue could taint the club for years to come if it is not dealt with quickly.
"As much as there may be issues in the dressing room (with Sunderland's black players) I think that's almost the smaller issue here," he added.
"The bigger issue is Sunderland Football Club and how it affects them... You worry that as a brand it may be stained by this appointment or the failure to properly account for it."
While stating that he expects Sunderland to survive given the quality of their squad, Hislop also voiced concerns about Di Canio's temperament and how it may or may not be suited to top-flight management.
Describing the former striker as "toeing the line between genius and insanity", Hislop said Di Canio was prone to "extreme reactions" to different situations that could sometimes blow them out of proportion.
"Given the pressures of the game, I wonder how that's going to translate in terms of man-management," he said.
"He had problems at Swindon, quite notably, but whereas that may be accepted, dismissed or explained at Swindon with players of that calibre who may be more willing to accept unfair criticism, I think it's completely different when you are talking about talented players who are wealthy in their own right...
"Much as his attitudes seem to have changed since the outbursts at Swindon, I don't think he'll be allowed even one at a Premier League club."
But Di Canio did get some high-profile support this morning, with Manchester United manager Sir Alex Ferguson saying he has been impressed by the Italian's footballing philosophy.
"I must confess to a liking for the fellow and his approach to the game," Ferguson told United Review.
"As I wrote the other week, he wears his heart on his sleeve and I like his football philosophy, wanting to play the ball on the ground rather than in the air.
"I have this picture in my mind of him being in the technical area pointing to the sky and then the ground in an effort to get his players to keep the ball down."
David James, another goalkeeper to have shared the West Ham dressing room with Di Canio, voiced his concerns writing for the Observer.
The former England stopper claimed Di Canio was unpopular with his team-mates as he "had a habit of behaving a bit like a dictator".
James said he never heard any hint of racism or politics from Di Canio while they played together but said his Roman salute at Lazio "confirmed my view of him as an unlikable person".