One of the Rebels' best this year, Louwrens has undergone biceps surgery after suffering the injury while making a tackle in their last-round win over Western Force.

Fiji international Frank Lomani is at No.9, with former Red James Tuttle on the bench.

Melbourne coach Dave Wessels named Andrew Deegan at five-eighth and shifted Matt Toomua to inside centre, saying he wants more from his backline in the Leichhardt Stadium clash.

He has also included big outside centre Campbell Magnay, with Billy Meakes starting in the reserves.

"We feel our young forward pack have been going well but we've lacked a bit of cohesion in our backs," Wessels said.

"Campbell is an out and out 13 and he will make a big impression for us linking the inside and outside of our attack.

"This is an important game for our backs who need to take a step up."

Meanwhile, the Brumbies have made two changes to their starting side, with flanker Tom Cusack and winger Andy Muirhead coming in for Will Miller and Tom Wright.

Coach Dan McKellar said they'd opted to rotate some players in the 23 following their after-the-siren win over Queensland.

"It's great to be able to call on the experience of Tom and Andy and have them slot back into the starting side this week," McKellar said.

"We've got depth and plenty of confidence across the whole squad and to be able to rotate a few bodies after a really physical game against the Reds last week is a positive for us. "

Currently third, the Rebels are looking to inflict the Brumbies' first loss of the season and start to lock down a finals berth.

"We want to start building some momentum as we did at the start of the year when we had a bit of a slow start and started to build into it," Wessels said.

"This game is important for that - the Brumbies are a team we like playing against and we've had a fair amount of success against - so this is an opportunity to try to start to play with some intensity."

MELBOURNE REBELS: Reece Hodge, Andrew Kellaway, Campbell Magnay, Matt Toomua (c), Marika Koroibete, Andrew Deegan, Frank Lomani, Isi Naisarani, Brad Wilkin, Josh Kemeny, Trevor Hosea, Matt Philip, Jermaine Ainsley, Jordan Uelese, Cameron Orr. Reserves: Efitusi Ma'afu, Cabous Eloff, Pone Fa'amaluli, Michael Stolberg, Richard Hardwick, Rob Leota, James Tuttle, Billy Meakes.

BRUMBIES: Tom Banks, Solomone Kata, Tevita Kuridrani, Irae Simone, Andy Muirhead, Bayley Kuenzle, Joe Powell, Pete Samu, Tom Cusack, Rob Valetini, Nick Frost, Darcy Swain, Allan Alaalatoa (capt), Folau Fainga'a, Scott Sio. Res: Connal McInerney, Harry Lloyd, Tom Ross, Will Miller, Ben Hyne, Ryan Lonergan, Mack Hansen, Len Ikitau.

Australian Associated Press