Former world champion and Sky Sports pundit Johnny Nelson is not in favor of the recent widespread chatter to have well known heavyweights of the past come out of retirement.

In the last few weeks, former champions Mike Tyson, Evander Holyfield and James Toney have all explained the desire to enter the ring again - at least on an exhibition level.

Among the bunch, Tyson has really turned up the heat with talks of an in-ring comeback, by releasing two viral training videos - where the 53-year-old heavyweight is displaying the power and speed of his prime years.

Tyson has been retired since 2015, when he was stopped by journeyman Kevin McBride.

And that's exactly what Nelson is cautioning the public about.

There are many fans who desire to see Tyson in a ring again, on any level, but they forget how badly he faded at the end of his career with knockout losses to Danny Williams and McBride.

""It's about the pace, that timing, that light-switch reaction. Once you've had time out to reflect and assess, you think 'I could do that'. But it's our mind playing tricks on us, because when you get in the ring and you come up against a youngster who's not as good as you, technically, but has more pace than you, he will do you every day of the week," Nelson told Sky Sports.

"We've seen Mike Tyson hit the headlines on the pads. And everyone's like 'oh my gosh, he's the don'. We're remembering the good times but we're not remembering the back end of the career when the body didn't switch as quick as it used to. The body didn't react as quick as it used to."