Western Force have lost two key players - scrum-half Alby Mathewson and winger Luke Morahan - for the important clash with the Rebels in Melbourne on Friday night.
Mathewson, who has been the form No.9 in the Australian conference, rolled his right ankle and Morahan damaged a hamstring in the battling 28-16 win over the Waratahs on Saturday.
Ian Prior, who signed from the Brumbies this season, will start on Friday and Justin Turner will make another return to the team, on the reserves bench, after four injury-hit years. Original third- choice scrum-half Ryan Louwrens is already out for the season with a knee injury.
The Force medical team will work overtime to get second- rower Sam Wykes (ribs) and prop Pek Cowan (leg), who were also hurt on Saturday, ready for Melbourne when they will be chasing a sixth successive win.
If they are not passed fit, coach Michael Foley's squad depth will be tested severely for the first time this year with forwards Hugh McMeniman and Chris Alcock already out with long- term injuries.
The 32-7 round-three win over the Rebels was the result that put the Force on the path to their unprecedented run of five wins.
Saturday's hat-trick hero Nick Cummins said the injuries would bite but it wasn't always about what names were on the player sheet.
"It's the feeling and attitude that the culture has brought and that's what the boys take into the game," he said. "Sometimes it's a mind thing. You get that right and everybody performs together."
Cummins said that despite their lofty position - second on the Australian conference and fourth overall - the Force would not take any expectations into the game against a Rebels side languishing at the bottom of the conference table with two wins.
"The Rebels games have been a little bit different since the last time we played them. They've got a lot of strike force and there's no way they are going to be the same team we played here," Cummins said.
"This is going to be similar to the Waratahs. It will be tough up front. These blokes are going to be hungry and that's what brings out good performance.
"We don't want to get ahead of ourselves, we've done a 180 in form. We've been due for a while.
"The culture has changed a bit here which has put on a bit of belief, a feeling of belonging, and everyone is buying into it.
"I've seen a few seasons here. There's been some dark times, some medieval times early on."
There's been some dark times, some medieval times " *Nick Cummins *