Bruce is currently at Hull City, where he is looking to mastermind a promotion campaign from the Championship.
However, Keys feels that United are missing a trick by not replacing Louis van Gaal with the 55-year-old boss.
Bruce was a United legend in his playing days and he knows Old Trafford and the demands of the club well.
And Keys believes that the Tigers boss would be perfect to take over the Red Devils, while Ryan Giggs continue to learn about management in a number two position.
"Why isn't Bruce in the running to manage Manchester United," Keys wrote. "I really can't think of a better qualified candidate. In so many ways he'd be perfect.
"If you're a United fan, before you start tweeting with abuse and rage, think about it.
"Bruce is United legend. He knows the club inside out. He was there before the glory years and at the start of an unprecedented era of success under Fergie. He helped lay the foundations for that glorious period at the club. He and Bryan Robson lifted the title trophy between them ending 26 years of hurt. Remember?
"He's seen the lot in a very successful managerial career. The highs of promotion and the devastation of relegation. He had Arsene Wenger and Arsenal rattled in the FA Cup final. How he initially got Hull into the P Lge is beyond me, but he's about to do it again. He's done it with Birmingham twice.
"That's like Fergie winning the title - arguably better, because he was operating with limited budgets.He's a character. He speaks well. He knows what United fans want. He understands the club and the DNA. He's a winner. He's got class. Little or nothing fazes him. He's exactly what United need right now. I'm certain Ryan Giggs would be happy to work with him with a view to finally taking over the reigns at Old Trafford."
United are believed to be on the look out for a new manager due to Van Gaal’s struggles.
The Dutchman remains in charge for the time being, but it seems unlikely that he will be at the helm at Old Trafford for much longer.
The Red Devils have looked out of sorts throughout the campaign to date, and their chances of making the Champions League next season look slim.
At the moment Jose Mourinho is the favourite to take over the United job, following his sacking as Chelsea manager last year.