Blink and you would have missed his first-team contribution last season, with three substitute appearances his sum total. Yet Lee Gilmour had made even less of a mark than that this time last year and went on to play in every game of Wigan's successful 1998 rugby league campaign.
It is a precedent that appeals to the 19-year-old Isherwood. "It shows that you will get a chance," he says. "And what I'd like to achieve is a permanent first-team place."
That might not be the wild ambition it sounds. With Gilmour earmarked to play in the centres this season and Denis Betts unlikely to be fit for the early rounds, the opportunity could be there for a newcomer in the second row.
In his brief tastes of the action against Huddersfield, Hull and Warrington, Isherwood showed enough to suggest that he will be able to cope.
"I didn't find it as daunting as I thought I would," he says. "But when you've got players like Andy Farrell in the changing-rooms with you it helps a lot. Denis Betts and Terry O'Connor have been really helpful as well."
Like Betts, Isherwood was a relative latecomer to the game, not playing until he was 12 and then being selected for the Leigh Town team after his first match.
Other clubs were soon tracking him, but there was never much doubt that he would be joining Wigan, where he has gradually and carefully been groomed for bigger things. He stood out in both the Academy and Alliance sides last season, coming under the influence of another former second-row forward of some note.
"I owe a lot to Andy Goodway," he acknowledges. "I learnt a lot from him last season that I needed to know before I could go any further."
When he started to train with the first-team squad midway through last season, Isherwood decided that his college course in psychology would have to be shelved, although one of the many things that Wigan like about him is that he is mature beyond his years.
"I couldn't carry on at college and give rugby 100 per cent," he says. "There will be time for that later."
Wigan point to him having done the right thing in clearing the decks by planning to take Isherwood to the first-team training camp in Lanzarote this month - the most solid indication yet that he figures prominently in Monie's plans. He has already shown that he is outstanding at his age level, playing for the Great Britain Academy side and being named as man of the match in a hard-earned victory across the Channel.
Now it is time to join the big boys and there are plenty at Wigan who believe that he will make a smooth transition.
The club's former chief executive, Phil Clarke - yet another distinguished back-row forward into whose orbit he has fallen - tells a story about rebuking Isherwood when he found him reading a down-market tabloid.
As an intelligent young man, he told him, he should be scanning something more like The Independent. "But I need to understand the thought processes of my team-mates," Isherwood retorted. A bright answer from a bright lad with a bright future.Reuse content