Melbourne's quest to stay atop the Australian Super Rugby conference has been dealt a blow with veteran prop Laurie Weeks ruled out for a month with a hamstring injury.
Weeks suffered the injury at training and will miss the Rebels' trip to Auckland to face the Blues on Saturday afternoon.
With a bye following, he will also be sidelined for their crucial clash with fellow contenders the Brumbies in Melbourne on May 13.
Irishman Jamie Hagan, who joined the Rebels this season, will make his Super Rugby starting debut while Tim Metcher comes onto the bench.
"Laurie won't play before the beginning of June but it's nice and easy for us as we bring Jamie Hagan into the starting side," said Melbourne coach Tony McGahan.
"He's been gathering time off the bench and has been going really well so he's pretty excited."
Balancing that bad news, the Rebels have been able to retain the same backline from their 36-14 win over the Cheetahs.
"It's a nice change because in eight games I don't think we've had the same backline two weeks in a row and those things are important," McGahan said.
While the Rebels are one point ahead of the Brumbies, the Blues anchor the competitive New Zealand conference.
However Melbourne prop Toby Smith said they were still formidable opponents, particularly at home at Eden Park.
"It's going to be a massive challenge," Smith said.
"(Prop) Charlie Faumuina especially, I've played against him a bit and he's a strong All Black and a very good scrummager so it's going to be tough for us."
While Melbourne were delighted to get a bonus point against the Cheetahs the realise they are far from the complete package.
"There's individual errors through the game we need to fix up and also to put an 80-minute performance together, because we haven't really managed to do that this season," Smith said.