The Scottish Premiership club parted company with Mark Warburton on Friday.
McLeish, who was manager for five years until 2006, insisted there has been no contact with his former club.
But the 58-year-old told Sky Sports: "When you get asked to come to a club like Rangers then its for sure a decision to turn that down."
McLeish, who was sacked by Egyptian Premier League club Zamalek in May, has emerged as the bookmakers' favourite.
And he was a television guest as Rangers, with caretaker Graeme Murty in charge, defeated Greenock Morton 2-1 to reach the Scottish Cup quarter-finals.
Asked if he was likely to be the new manager, McLeish replied: "You never know. It is purely coincidence that I'm here today.
"You called me a couple of weeks ago to come and do this game and I then find there's been some events happening at Ibrox the last couple of days."
McLeish was also asked if Rangers had been in touch since Warburton departed on Friday.
"No," he said. "Obviously there's a lot of speculation, but at the moment there's nothing I can update you on apart form the fact that I'm here and it looks more than a coincidence, but it is a coincidence."
McLeish won two Scottish titles as Rangers manager and the Glasgow club also won five knock-out trophies during his tenure - the Scottish Cup twice and League Cup three times.
The man who has also managed Motherwell, Hibernian, Scotland, Birmingham City, Aston Villa, Nottingham Forest and Genk hinted that a return to Ibrox would be an attractive prospect.
"I am a Rangers man, so you obviously have to keep that in consideration," he added.
Rangers chairman Dave King has claimed that the club accepted Warburton's resignation after the manager's representative had talks with Nottingham Forest, while the Englishman denies he resigned.
The Glasgow side lie third in the Scottish Premiership, 27 points adrift of city rivals and holders Celtic, and King said Warburton's team had not reached the targets expected of them.
Former Rangers players Gordon Smith and Barry and Derek Ferguson have described McLeish as the ideal candidate to take over.
Alex McLeish admits he would find it difficult to turn down Rangers should he be asked to become manager at Ibrox for a second time.