Team manager Martyn Fowler has confirmed a number of changes to the side beaten by the Ospreys last time around with Tom Riley, the Pontypridd centre, amongst those who miss out.
Having said that there is a strong Ponty influence with the likes of Dai Flanagan, Chris Clayton, Rhys Shellard, Goodfield and Greg Evans all included.
If that contest is a tough one to casll, it could be even harder to predict the winner at Bedwas tomorrow night where the Dragons, who were defeated in injury time by the Ospreys two weeks ago, take on Blues South under 16s.
Phil Williams and Ben Warburton continue to pose a threat for the Blues in midfield, but coach Gafyn Cooper has made changes to the side that lost out to the Scarlets at Stradey Park last time around.
Will Williams, of Bassaleg School and Llandaff North, comes in at full back, whilst amongst those included at forward are Marco Ciriello (Cardiff High School and Llandaff North) and lock Louis Rappa of Llanrumney School and Rumney Rugby Club.
After suffering a disappointing home defeat at the hands of the Scarlets on the opening night, the Blues North had the night off two weeks ago. However, they are back on duty tomorrow night with a home game against the Ospreys at Aberdare.
Coach Dale McIntosh was pleased with certain areas of his side's performance against the Scarlets but said,
"We were a bit sloppy at times, but the boys will learn from that and it's up to us to make sure they put things right.
"Having said that, it was their first game and we can't be too critical. The Scarlets were a very good side."
The under 18 Blues have another tough assignment - this time they take on the unbeaten Scarlets who are fresh from a surprise but fully deserved victory over the Dragons.
Tuesday November 23 (7pm kick off)
Blues North Under 16s v Ospreys (Aberdare RFC)
Dragons v Blues South Under 16s Rhymney RFC (Gwent) Blues Under 18s v Scarlets (Pontypridd RFC)
Wednesday November 24 (7pm kick off)
Scarlets v Blues Under 20s (Llandovery RFC)
Blues South under 16s: W Williams; J Egan, B Warburton, P Williams (capt), J B Morris; J Thomas, R Dyer; G Spears, S Barry, P Jones, L Rappa, S Warburton, C Holcombe, R Watts-Jones, M Ciriello. Replacements: S Spavin, L Griffin, S Regan, E Morris, C Llewellyn, G Price, J Bird
Blues North under 16: L Hughes; B Powell, C Lewis, A John/O Lewis, M Powell; N Rees, S Parry; C Johns, R Williams, D Matthews, J Edwards, M Alazawi, L Davies, R James, C Dacey. Replacements: S Beahin, Luke Davies, D Hinds, R Dunn, T Price, L Collins, J Thomas.
Blues under 18s: K James; J Bird, J Gough, L Thomas, C Thorne; C Ashton, C Bala; S Thomas, M Jones, K Jenkins, B Davies, J Down, J Cullen, D Franks, M Larson. Replacements: J Davies, L Ford, A Shields, J Groves, N Eaves, R Jenkins, A Fowler
Blues under20s: J Roberts; C Clayton, G Evans, D Hewitt, C Czekaj; D Flanagan, T Dickens; R Gill, D Goodfield (capt), P Osborne, S Wahdan, W Jones, D Thorn, R Shellard, A Powell. Replacements: R Wood, G Williams-Davies, N Trevett, G Jones, M Bailey, A Murphy, C Dicomedis.