Former Saracens centre Tim Streather retires from rugby union on medical advice with a persistent knee injury.
Premiership champions Exeter will begin their title defence at Gloucester when the 2017-18 season starts on 1 September.
Saracens re-sign Australian prop Kieran Longbottom on a one-year deal from Premiership rivals Sale Sharks.
Scotland international wing Sean Maitland signs a new contract with Saracens to stay at the club until 2020.
Audio & Video
Wales full-back Liam Williams plays his last game at Parc y Scarlets on Saturday before leaving Scarlets for Saracens, so we pick out some of his best moments for the Llanelli-based region.
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What's on BBC Sport this week
This week's sport on the BBC includes the World Aquatics Championships, England v South Africa in the third Test and the Challenge Cup semi-finals.