It could all be over by Christmas for Sheffield's reigning WBO cruiserweight champion. It will be if promoters can't find him a bout in between his September title defence date with German challenger Rüdi May and the turn of the year.
Nelson who has reigned as world champion cruiserweight for a hugely creditable five years, is adamant. "If they come to me and offer a fight in March or April, I'll say 'no thanks' and walk away."
At 37, no-one would blame him. He has fought 57 times, defended the WBO belt 11 times, been hero-turned-villain-turned-hero.
Veteran trainer Brendan Ingle insists that Nelson, the hapless amateur who turned ultra-proficient pro, is the biggest success story to emerge from his Wincobank gym. No matter that Herol Graham and Naseem Hamed preceded him into boxing's big time.
Graham quit and mistakenly tried again; Hamed quit all but talking about it. Nelson knows the clock's against him and is prepared as he could be for the final bell.
"This time last year I said I've got 18 months left at the top level, when I know I'll be able to perform at that level," he said. "Over the past three years, I've boxed once a year. That's not the fault of my training. I don't know who to blame but I cannot fight just once a year. The older you get the harder it gets. I can't afford to be getting ring rusty."
Alarm bells raung in Nelson's head when he scraped a draw with Guillermo Jones in 2002. Since then only one more fight has been fought.
"I've said that if things carry on as they are I won't be boxing next year," he said.
"If they could squeeze me a fight in after September before Christmas, fine.
"I've been the champion for five years and it's just not logical that at 37 I should be boxing once a year."
Nelson will go to Germany to meet the challenge of May. It will be the last fight under his current contract with Frank Warren.
"John Ingle and Dominic Ingle have a few irons in the fire," he revealed. "I know there are opportunities there. I know Frank is interested and wants to continue with the contract but anyone with commonsense wouldn't carry on like this. I need to be boxing every three months."
Whether Nelson on or not boxes beyond September remains in the balance but it won't be a fighter broken in any sense of the word who departs the ring.
He's comfortably off and has been offered TV work following fights with Sky Sports.
"It will be a very easy decision. I love the game but I'm not an idiot," he said.