Whilst the Dragons appear to be out of the hunt, they have yet to register a victory this term, the other four regional sides all have a chance of making it through to next month's final at Sardis Road.
Victory for the North would certainly put them in poll position, but if the Ospreys can secure a valuable away win at Abercynon, they would take over as favourites to win the pool.
Dragons: S Bevan; J Morris, M Jolly, L Smalley, A Cooper; L Robling, J Evans; L Bacon, L Jones, A Yule, A Hughes, R Wilson (Capt), R Griffiths, C Penna, G Evans
Replacements: L Ford, T Rusga, G Kemp, R Paul, L Davies, M Cummings, G Hobbs
Blues South: E Jones; F White, N Gumbleton, T Luck, B Andrews; D Lakin, S Curtis; M Savery, J Deabrau, J Tomlinson, K Hopkins, T Connolly, J Wilson, R Fenton, R Tucker
Replacements: L Davies, A O'Malia, A Taylor, D Crimmins, J Lewis, A Cooke, D Evans
Blues North: H Thomson; O Williams, A Lewis, S Campbell, B Jones; J Griffin, K Marmion; L Smout, C Williams, O Davies, M Cook, J Barley, D Barry, T Young, O Sheppeard
Replacements: T Emmanuel, S King, C Hill, J Gibbon, E Sherlock, A Webber, J Wills
Ospreys: T Prydie; B Barlow, S Hughes, D Howells, E Walker; O Williams, R Jones (Capt); J Martin Fraser, R Curtis, D Saines, L Joseph, B Davies, R Kehoe, M Sully, D Baker
Replacements: D Davies, M Morgan, B Davies, S Pick, R Thomas, M Carpenter, L Evans