Bath boss Gary Gold has voiced his admiration for London Welsh and how they have adapted to life in the Aviva Premiership.
Gold takes his team to the Kassam Stadium on Sunday, a ground where the Exiles have already beaten Exeter and collected losing bonus points against Gloucester and Saracens this season.
"It is going to be another tough encounter for us, especially with their ability to dig in for the win at home," Gold said.
"They (London Welsh) are a good group of players, they are well coached and have a great attitude to work hard for each other. I've been been impressed by what they have done this season."
Wales international Gavin Henson moves from fly-half to centre for London Welsh, with Gordon Ross taking the number 10 shirt. Full-back Tom Arscott, meanwhile, has recovered from injury so recent recruit Tom Voyce reverts to a more familiar wing slot against one of his former clubs.
Bath welcome back Matt Banahan to their midfield following an eight-week injury absence, with prop Anthony Perenise replacing England squad member David Wilson, but injuries sideline flankers Carl Fearns and Francois Louw, so Stuart Hooper and Will Skuse deputise.
Meanwhile, Wasps rugby director David Young has no doubt his team will need to take a considerable step up when they tackle Saracens at Vicarage Road. Wasps have won four successive games in all competitions - their best results sequence since December 2010 - but they last recorded a Premiership away win 12 months ago.
"While it is good to be heading to play Saracens with some momentum behind us, we are under no illusions as to how much improvement we will have to make this weekend," Young said.
Wasps' England flanker James Haskell returns after missing the bonus point victory over London Welsh last weekend due to illness, but injuries sideline centre Lee Thomas and scrum-half Joe Simpson. Chris Bell and Eliot Daly team up together in midfield, with Charlie Davies wearing the number nine shirt.
Saracens, meanwhile, are without their sizeable England contingent, and Wales prop Rhys Gill is absent injured as they play their first fixture of the season at Vicarage Road. But Charlie Hodgson returns at fly-half, with Chris Wyles and Kameli Ratavou also starting behind the scrum, and prop Matt Stevens switches from tighthead to loosehead in a team that also includes new Scotland skipper Kelly Brown.