Their hosts have not lost since going down to Bedford on the opening day of the season, winning their next seven league games.
Doncaster, handily placed in third, have made two changes to the side that won 19-10 against London Scottish in their last game.
Fly-half Declan Cusack makes his long-awaited return, replacing Ollie Bryant after a lengthy spell out injured since fracturing his cheekbone in the second game of the season at Nottingham.
The only other change to the Knights starting XV sees club captain Matt Challinor reclaim his position in the second-row alongside Jon Phelan.
Full-back Paul Jarvis said: “We just need to carry on doing what we’ve been doing – we’re still gelling as a squad and finding our best combinations.
“It will be a huge battle upfront and that could well swing the game in either side’s favour – judging by what Bristol have been saying they will back themselves in that regard and we have to be ready for that from the off.
“It will be a physical challenge, we know that they’ve got a lot of big boys and some strong ball carriers; but if we can match that and frustrate them then who knows?
“We’re facing a very different beast tomorrow make no mistake about that.
“But if the boys can front up, and I’m sure they will, we’ve definitely got it in us to knock them back and match them for physicality.”