Current cup holders, Ulster, who face last season's champions the Scarlets at Ravenhill on Friday night, could end all the speculation with an eighth straight home win in all competitions that would secure their place in the top eight.
However the Scarlets will have their eye on a home draw in the Celtic Cup and should Ulster slip up, the Blues could yet make the play-offs. They face the Borders in Friday's other game and they need to win to stand any chance of extending their season.
An Ulster slip up could also let in Connacht who face the Dragons on Saturday evening. The Newport based side still harbour hopes of a top four finish but will need to up the performance of recent weeks when they have shipped 87 points in three successive defeats.
Saturday's other games see Leinster travel to Glasgow and Edinburgh in Munster. Both Irish sides have secured home quarter finals, however the Scots will be hoping that the Scarlets and Dragons slip up letting one of the Scottish sides take a home draw with them both currently locked on 44 points.