This is traditionally the biggest game in the Magners League and Scarlets are desperate to regain some local pride after losing all three games to the Cardiff Blues last season .
Online bookies however make Cardiff strong favourites with William Hill offering the best odds of 2/7 about a home victory .
Both teams have named strong line ups and the game is covered live on BBC2 Wales with kick off at the Cardiff City Stadium at 8.05pm .
Scott Andrews will start for Cardiff and Chris Czekaj is named at full back and the Blues will want to put their 27-20 Heineken Cup defeat at Castres quickly behind them .
Scarlets will field a side showing 10 changes, three of them positional, from the team which was beaten 46-10 at Leicester in the Heineken Cup last week.
Rees, Jones, Regan King and Martin Roberts are all named on a strong replacements bench, with Rhys Priestland swapping from full-back to fly-half and Ken Owens coming in at hooker.
Cardiff are currently in second place in the Magners League with Scarlets only two points behind in fourth position .
It should be a bruising encounter but expect Cardiff to prevail at the odds but perhaps not by a landslide .