The 35-year-old's 15-season international career could be at an end but former Blues boss Dai Young hopes his old Wales and Lions team-mate will be given another chance to join Gareth Thomas and Stephen Jones as a Welsh centurian.
"Knowing the guy and knowing how much he's put into Welsh rugby, it would be a massive shame if he didn't get to 100 caps," said Young, who coached Williams for eight years and toured Australia with him as a Lion a decade ago.
"I'd have thought he'd have to go searching for that one more.
"To be honest, it might have been nice if he'd had his 100 caps now, not worried about international rugby and just enjoyed it.
"It's a nightmare of a job for Warren to pick 30 players out of a squad of that quality - my only disappointment is that Martyn could miss out on getting 100 caps and I think he deserves that."
Young may have left the Blues for London Wasps this summer but he is convinced Williams will go out with a bang in what will be his last year of professional rugby.
The veteran openside hasn't yet called time on his stellar Wales CV and Young believes we'll see another ultra-consistent campaign from one of the country's favourite sons.
"Martyn will bounce back. Yes, he'll be disappointed about not going to the World Cup but he'll bounce back and he'll enjoy his rugby at the Blues. I've no doubt about that because we discussed it before I went.
"Martyn has never ever played poorly. Some games he's good, some games he's very good. I think he'll have a big a year for the Blues."