Northampton kept alive their hopes of playing in the Champions Cup next season with a hard-fought 21-15 win over Connacht.
Munster finished top of the Guinness PRO12 thanks to a 50-14 thrashing of Irish rivals Connacht at Thomond Park.
With 11 Irish players away with the Lions, Joe Schmidt has handed eight uncapped players a chance to show what they can do.
Munster make up more than a third of the Guinness PRO12 team of the season with six of their players included.
Scarlets sauntered into the Guinness PRO12 play-offs with a 30-8 bonus point victory over error-strewn Connacht.
Connacht's Bundee Aki has been handed a three-match ban for misconduct.
Eoin McKeon and Darragh Leader have signed contract extensions with Connacht.
Leinster secured a home semi-final in the Guinness Pro12 after running in five tries in a 37-24 victory over Connacht.
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