Four successive defeats for the west country club mean they are now among a congested pack effectively chasing two spots, with leaders Leicester and second-placed Gloucester looking safe bets to secure semi-final berths.
But victories in their remaining three homes games against Northampton, Worcester and Leicester at Ashton Gate should guarantee their season extends into May.
Bristol head coach Richard Hill said: "Danny has looked very sharp in training and he has gained a lot of confidence from his time with the England Sevens set-up.
"The coaches have confidence in him and so do the rest of the players. He poses a threat to opposition defences."
Gray will be partnered at half-back by Shaun Perry, who is back from England RBS 6 Nations duty, while Dave Hilton, Mark Regan, Roy Winters, Gareth Llewellyn and Alfie To'oala all return to the pack after missing last Sunday's 36-5 defeat against Saracens.
Hill added: "At the end of the day, we are still third. We've got ourselves into this position and we are set up where we want to be.
"We've got the best run-in of all the top six clubs - it's just a question now of whether we are good enough to win at least two of the remaining games to stay in the top four."
Northampton slipped to the Premiership basement courtesy of a draw against Sale Sharks last Saturday after nearest rivals Worcester fought back to defeat Newcastle 23-21 and climb off the bottom.
Saints' next three league games are away from home against Bristol, Newcastle and Wasps, and with Worcester having won three Premiership fixtures on the bounce, momentum is now with the Sixways club.