Drew Hickey also makes a return to the back row at blindside after recovering from concussion, with captain Pat Sanderson switching to openside.
Phil Murphy moves up from the bench to start at lock and Darren Morris, who was a late withdrawal from the Gloucester game, returns in the front row alongside Chris Fortey, who this week signed a new two-year deal with the club.
Director of Rugby John Brain said: "Bath will be a big test up front, they have a very able pack of forwards and a very good lineout. That will be the first key battle in the game. If we can make sure our own set piece is functioning well we have a very good chance.
"We might need to win four, five or even six of the remaining six games to stay in this league but that is possible," he added. "It has been done before and it is something we are capable of doing."
Worcester Warriors team to face Bath Rugby:
01 Darren Morris, 02 Chris Fortey, 03 Tevita Taumoepeau, 04 Craig Gillies, 05 Phil Murphy, 06 Drew Hickey, 07 Pat Sanderson (c), 08 Kai Horstmann, 09 Matt Powell, 10 James Brown, 11 Thinus Delport, 12 Gary Trueman, 13 Dale Rasmussen, 14 Aisea Havili, 15 Shane Drahm
Replacements: 16 Tony Windo, 17 Aleki Lutui, 18 Tim Collier, 19 Tom Harding, 20 Nick Runciman, 21 Mark Tucker, 22 Lee Best