The former England second-row turns 37 in August and is the longest-serving player in Super League having started out with his hometown club in May 1999.
Jones-Buchanan, who has won seven Grand Finals with Rhinos, is in their squad for the trip to Hull FC and could become only the 14th player in the club’s history to reach the landmark, following on from former team-mates Kevin Sinfield, Rob Burrow and Danny McGuire.
One of the toughest and most durable players in the competition, he has said he hopes to keep “plodding on” in 2019 although has not yet made a firm decision.
However, McDermott said: “I think when Jamie Jones is running down the field and his leg drops off and he has to turn around and go pick it up that is when he’ll retire.
“That’s when he’ll think ‘That’s it!’ He’s loving it and loving the tough moments as well.
“He’s playing really well. I’m not after retiring him. If he wants to say this is his last season that’s up to him. But if he wants to go again next year there’s a conversation to have.
“I don’t think anyone would disagree with that especially with the wave of talent we’ve got who are all learning and benefiting from having people like Jonesy in the team.”
McDermott continued: “For him to reach 400 games is massive. It is for him as he’s spent a lot of his time strapped up, in a cast and laid up.
“He must have been playing 27 years or something; I played against Jamie Jones which gives an indication of how old he is.
“When Sinfield, Kylie Leuluai and Jamie Peacock were here, he was always a real important bloke in that group. You couldn’t imagine the team, squad or club without him.
“He was never just another rank and file soldier. He had that leadership quality in him then but he never got chance to show it. He didn’t need to show it.
“We never unearthed it but since those three retired – and especially over the last couple of seasons – he’s been fantastic.
“He has a real reverence about him and when he speaks people listen.”
Champions Leeds have won on their last five visits to KCOM Stadium and if they do so again tonight, after last week’s late 9-8 home loss to Wigan, they will move back into the top-four.
Hull, however, will replace them in fifth if they can gain revenge for last month’s narrow 20-16 defeat at Headingley.
FC head coach Lee Radford knows where it could be won or lost.
“Leeds are the quickest team out of the blocks in the competition,” he said.
“They have scored more tries than anyone else in the first 20 minutes and more tries than anyone else from kicks.
“If we concede from a kick in the first 20 minutes you are going to see one very frustrated coach.
“But we’re confident our best will come.”
Meanwhile, former Leeds and Great Britain prop Ryan Bailey, 34, has joined Leigh Centurions from Workington Town.
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