At the Arms Park the Blues have lost just one of their past nine games in the Celtic League and that was in this equivalent fixture last season.
Llanelli Scarlets have done the same in losing their last four games in the Celtic League and European Cup, with their last win coming on 25 September when they beat Edinburgh 37-16 at Stradey Park.
The Scarlets won both encounters against the Blues last season.
Meanwhile Blues assistant Coach Geraint John explained that there were several factors delaying the choice of the starting line-up.
‘The Wales team management have released Craig Morgan, Robert Sidoli and Gareth Williams from their training camp so they will be part of the equation,’ he said. ‘However there is some uncertainty about the availability of Rhys Williams.’
‘Though he is not in the Wales squad of 22 to play South Africa, he has been told that he is ‘number 24’ and has been required to stay at the team hotel and to attend the international.
‘If there are no injuries our understanding is that he will be allowed to play for the Blues on Sunday. Rhys certainly wants to play and the rest of our squad accept that he will be drafted in even if it is at the eleventh hour.’
John added that two definite non-starters are wings Jonny Vaughton (hamstring) and Nick Walne (knee). Ryan Powell played 50 minutes for Llanharan at Neath on Wednesday and reported no ill-effects.
Blues: Rhys Williams, Craig Morgan, Matthew Nuthall, Fereti Tuilagi, Shaun James, Dean Dewdney, Lee Thomas, Nick Macleod, Richard Smith, Ryan Powell, John Yapp, Andrew Lewis, Rhys Thomas, Gareth Williams, Ben Evans, Martin Jones, Robert Sidoli, Deiniol Jones, Craig Quinnell, Nathan Budgett, Nathan Thomas, James Malpas, Kort Schubert, Robin Sowden-Taylor
Scarlets: TBC
