Tom Shanklin believes Wales are taking a risk by holding out hope that centre Gavin Henson will be be fit to play any part in the Rugby World Cup.
Henson has had surgery as he dislocated a wrist in Wales' 19-9 win over England and could be out for up to eight weeks.
The 29-year-old will remain in Welsh camp but his double-Grand Slam winning centre partner Shanklin is cautious.
"You probably need more than 31 minutes to really warrant a place for the World Cup," said Shanklin.
It is unlikely that Henson will be named in Warren Gatland's 30-man squad when the Wales coach announces it on 22 August after Saturday's final World Cup warm-up against Argentina in Cardiff.
Henson will stay on Wales standby but would only travel to New Zealand should Gatland's squad suffer an injury in the backs.
Wales believe Henson will be fit within six to eight weeks - and the Welsh play Namibia in their third Pool D clash on 26 September before completing their group stage fixtures with a game against Fiji six days later.
Should Henson require a full eight-week recovery period, then he could return on the weekend Wales play a World Cup quarter-final if Gatland's team qualify from their pool.
Shanklin, Henson's midfield partner when Wales won Grand Slams in 2005 and 2008, was impressed by his old team-mate's display against England in Cardiff on Saturday.
But Wales' most-capped centre feels Henson's lack of rugby in the last two-and-a-half years counts against him as he has suffered a series of injuries since his 18-month rugby sabbatical.
"I feel disappointed for him [Henson] because he had some nice touches," said Shanklin.
"He had the ball in his hands, he looked hungry. He was solid in defence. And we saw little glimpses. The worst thing is apparently he's really fit.
"You've got to feel for him a little bit because he has worked pretty hard to get himself back in good shape.
"It's 30 minutes of rugby and that's to get your place in the World Cup squad.
"It could be worth it [naming Henson in the 30-man squad] if you've seen their form leading up to this.
"The problem is that no-one has seen or tested Gav up until now and he needed this game time. That's a decision Warren and his team have to make.
"They haven't ruled him out, but that sort of shows how highly Warren, Rob [Howley] and Shaun [Edwards] think of him."
Henson has suffered World Cup disappointment twice, in 2003 and 2007, and was up against midfield rivals Jamie Roberts, Jonathan Davies, Scott Williams and the versatile James Hook for a centre berth.
Wales' preliminary World Cup squad
Forwards: Scott Andrews, Gethin Jenkins (Blues), Lloyd Burns (Dragons), Huw Bennett, Ryan Bevington, Richard Hibbard, Adam Jones, Paul James (Ospreys), Ken Owens, Craig Mitchell (Exeter), Bradley Davies, Sam Warburton, Martyn Williams (Blues), Luke Charteris, Danny Lydiate, Toby Faletau (Dragons), Ryan Jones, Alun Wyn Jones, Jonathan Thomas, Justin Tipuric (Ospreys), Josh Turnbull, (Scarlets),Gareth Delve (Melbourne Rebels), Andy Powell (Sale Sharks).
Backs: Michael Phillips (Bayonne), Lloyd Williams (Blues), Tavis Knoyle (Scarlets), Jamie Roberts (Blues), James Hook (Perpignan), Jonathan Davies, Stephen Jones, Rhys Priestland, Scott Williams (Scarlets), Leigh Halfpenny (Blues), Lee Byrne (Clermont Auvergne), Aled Brew (Dragons), Shane Williams (Ospreys), George North (Scarlets).