Scrum-half Robbie Shaw has re-signed for Bristol on a short-term deal until the end of the season.
The USA international, 31, made 42 appearances during his two seasons with the club between 2009 and 2011.
He has been playing for Championship rivals Esher and will be loaned back to them immediately but can be recalled by Bristol when required.
"We know we can rely upon him if he's called upon," said director of rugby Andy Robinson.
"Robbie's arrival gives us extra depth and we've worked swiftly to ensure we go into the play-offs with four quality scrum-halves at our disposal."
Bristol completed a similar deal on Monday for Cornish Pirates scrum-half Tom Kessell, who will remain a Pirates loan player and is likely to only be available to Bristol for the play-offs before joining Northampton Saints in the summer.
Robinson has been looking for half-back cover after Luke Baldwin's defection to rivals Worcester Warriors.