With four key backs sidelined for at least the next four games, former Wales skipper Young has turned to diminutive Test winger Williams to spark his struggling backline.
'We've put Rhys at No 13 because we've been lacking a cutting edge in recent matches,' Young said ahead of tomorrow's Celtic League game against Munster at their Thomond Park fortress. 'We're trying to get our game-breakers into the game as quickly as possible, and Rhys is obviously a game-breaker. You all know how good he is with the ball in his hands.'
The talented Robinson brothers were up to two months away from playing again, he said. Elder brother Jamie has knee ligament damage, while Nicky has a viral infection.
'Nicky has seen another specialist and he has put him on a six-week programme, so it will be at least that long before he starts full training again,' Young said. 'I don't know what virus it is - it's two very long words - but it leaves Nicky feeling like me every day. He's absolutely knackered.
'He's very frustrated and depressed because he knows he's on the edge of something big in terms of his international career.'
Blues skipper Martyn Williams said his side were confident ahead of tomorrow's match, but knew how tough coming home with the points would be.
'Munster are getting back into peak form and there's probably no tougher place to go in Europe than Thomond Park,' he said. 'Llanelli's effort against them a couple of weeks ago has given us some hope - they held Munster for most of that game.'
For Munster, Rob Henderson, Jim Williams and Paul O'Connell all return from injury. Henderson takes over from Mike Mullins in the centre and he will be partnered by Shaun Payne who switches from the wing. John Kelly retains his place on the wing having come on as a replacement centre for James Storey against Glasgow last weekend.
Up front, O'Connell comes into the second row with Tom Bowman missing out. Williams, recovered from the elbow injury he received against Leinster, replaces Alan Quinlan in a back row that sees Denis Leamy continue in the openside position and Anthony Foley at No 8.
Coach Alan Gaffney said: 'Denis and Jim have been outstanding in their appearances to date.
'Last week we felt Denis needed a rest and Jim wasn't available but now he is. There is also the question of giving players the opportunity to stake a claim and to that end we are trying to give squad members as much game time as possible.'
Munster: C Cullen; J Kelly, S Payne, R Henderson, A Horgan; R O'Gara, P Stringer; M Horan, F Sheahan, J Hayes; T Hogan, P O'Connell; J Williams, D Leamy, A Foley (capt)
Replacements: J Flannery, G McIlwham, T Bowman, A Quinlan, M Prendergast, P Burke, P Devlin
Cardiff Blues: C Morgan; J Vaughton, R Williams, T Shanklin, F Tuilagi; L Thomas, D Dewdney; G Jenkins, G Williams, M Jones, C Quinnell, R Sidoli, N Thomas, M Williams (capt), K Schubert
Replacements: A Lewis, R Thomas, D Jones, N Budgett, R Smith, N Macleod, S James