Prop Darren Morris is handed a starting spot with Tony Windo on the replacements bench and Chris Horsman returns to the front row following his RBS Six Nations exploits with Wales.
Following the final training session on Friday afternoon, scrum half Matt Powell has also been ruled out through injury. The starting number nine shirt is handed to Nick Runciman.
Director of Rugby John Brain said: "We are playing well and we have got to make sure we are keen to get going again after the break. The start to the game will be crucial and that is the key to re-establishing some momentum.
"It is close at the bottom but all I'm concerned about is us, we know if we approach the game in the right way we are in with a real shout of winning it.
"It is effectively another cup final but we don't think about the significance of the outcome, we have a clear focus on what we need to do to win that match."
Worcester Warriors team to face Bristol Rugby:
01 Darren Morris, 02 Chris Fortey, 03 Chris Horsman, 04 Craig Gillies, 05 Phil Murphy, 06 Kai Horstmann, 07 Pat Sanderson, 08 Drew Hickey, 09 Nick Runciman, 10 James Brown, 11 Thinus Delport, 12 Mark Tucker, 13 Dale Rasmussen, 14 Aisea Havili, 15 Shane Drahm
Replacements: 16 Tony Windo, 17 Aleki Lutui, 18 Richard Blaze, 19 Gavin Quinnell, 20 Jonny Arr, 21 Thomas Lombard, 22 Lee Best
Coral.co.uk, the official betting and gaming partner of the Guinness Premiership are offering a free £10 bet on your team this weekend when you open an account plus you could earn your club up to £20 in return.
Bristol have lost at home just once this season and are odds on favourites at 1 to 2 to win their match this weekend against Worcester Warriors. Local rivals Warriors are looking for their fourth straight win in the league, a sequence that has lifted them of the foot of the Premiership table. Coral.co.uk, the official betting and gaming partner of the Guinness Premiership price Worcester Warriors at 8 to 5 to win the match. Bristol's 41-11 win at Sixways in September was their first win over the Warriors since May 1999 whereas Worcester have won on their last two visits to Bristol.
Bristol 1 to 2 favourites
Worcester 8 to 5
Draw 18 to 1
Bristol v Worcester(+6 points)
To place a bet on this game please visit www.coral.co.uk/rugby for all the betting odds as well as all other Guinness Premiership matches this weekend. Plus open a new account and win a £10 FREE BET and for Coral.co.uk will double that and provide your favourite Guinness Premiership club with £20 for every account opened.