The Dragons currently lie third in Pool 5 behind this weekend's visitors who both have 5 points and can go ahead of them if they win this weekend giving them the advantage for next week's away clash.
The Scarlets are away to Glasgow this weekend knowing that they have to start picking up points to stand a chance of making it beyond the group stages.
Last season, this match would have been considered a routine run out for the men from Stradey, having beaten the Scottish team comfortably home and away in the Celtic League.
However, with a 40-29 defeat still hanging over their heads from this year's Celtic League tie two weeks ago, Gareth Jenkins' men will be wary of their opponents and looking to improve on their form with the return of key internationals to the side.
The Blues travel to Gloucester four points adrift of their opponents at the bottom of Pool 6 and in a similar predicament to the Scarlets. The Blues are desperate to pick up points in order to make progress in the Pool table. A win away to Gloucester would put them level on 5 points.
The Ospreys are still looking to transfer their Celtic League form to the Heineken Cup as they host NEC Harlequins on Saturday. Like the Blues and Scarlets, the Ospreys have only one point from their opening two games but can steal a comfortable lead on this weekend's rivals if they win as Harlequins have only amassed three points so far this season.