London Welsh will be relegated from the Aviva Premiership at the end of the season following a 29-14 loss to Bath on Sunday.
Sale recorded a highly-important 23-6 Aviva Premiership win over Gloucester at the AJ Bell Stadium on Sunday.
Leicester and England centre Manu Tuilagi is likely to miss the rest of the season with his groin injury.
Saracens moved second in the Aviva Premiership standings after a 42-14 hammering of Harlequins at Wembley.
Geoff Parling's second-half try and the boot of Freddie Burns helped Leicester Tigers to a 25-18 victory over Exeter.
London Irish held on to record a narrow 22-21 victory over Newcastle Falcons in an incident-packed contest in Reading.
Northampton hope George North will not be sidelined for too long after suffering another head injury against Wasps on Friday.
A controversial red card for Nathan Hughes saw Northampton come from behind to beat Wasps 52-30 at Franklin's Gardens.
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