Wigan Athletic chairman Dave Whelan says Rangers fans should be wary of Mike Ashley because the owner of a club should always be a supporter.
Ashley has a 10% stake in the Ibrox club but is widely regarded as being the most influential shareholder, having loaned the club £2m last week.
"If I was [a Rangers fan] and a stranger from England started buying my club I'd be worried," said Whelan.
"I'd ask myself 'Has he got Rangers Football Club at heart'?"
Whelan had business dealings with Rangers in the past through JJB Sports.
Ashley now has a retail deal of his own at Rangers through his Sports Direct brand.
Whelan says any investment in football should be welcomed, but questions why the Newcastle owner is getting involved with the Ibrox side.
"It's like me and Wigan Athletic, I am Wigan through and through and I'll do anything I can for them," he added.
"It's that kind of owner that supporters want. Is Mike going to be like that? He's not been like that at Newcastle United and the Newcastle supporters are similar in a lot of ways to the Rangers supporters. I'm at a little bit of a loss and only time can answer it.
"He got involved in Newcastle United and I was a bit surprised when I saw he had a big interest in Rangers. It's not for football, it's obviously something commercial.
"Rangers are a massive club and have massive retail sales and the supporters really do buy the Rangers kit and they support that club through and through. Could it be something to do with that? It's a very strange one.
"The one thing you've got to remember is Mike Ashley's a very very shrewd gentleman. He's not a real football man, he's the first to admit when I talk to Mike that he doesn't really understand the game."
Whelan has no doubts about Ashley's abilities as a businessman, but remains bemused by the Englishman's desire to get involved in Scottish football.
"[Mike Ashley] is a very nice guy, he's strictly honest," Whelan added.
"I have dealt with him because he bought JJB from me. He's ruthless, yes, and you've got to be ruthless when you're in business like he is.
"At Rangers I don't know what the big pull is because he can only own 10% I think. Can you run a club with only 10%? I don't think so.
"Do the Rangers fans want him to buy that club and do they want him to be chairman? I have my doubts on that."
There has been speculation that Ashley has increased his interest in Rangers in the hope of the club one day moving to the English Premier League, and that is a move Whelan would welcome.
"It would great for the Premier League if they extended the league, don't put anybody out, and bring Celtic and Rangers in," he said.