The Wallabies could be in line for a major boost with prop Taniela Tupou likely to be available for the second Test.
Tupou missed the first Test as he continues his recovery from a calf injury suffered during Super Rugby Pacific.
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However, he could be thrust straight back into the starting side after Allan Alaalatoa departed the field in the first half with a concussion.
Under World Rugby's new concussion laws, players must sit out 12 days before returning, leaving the Brumbies skipper all but ruled out for Saturday's second Test.
“We’re very confident that Taniela will be available, which is good,” Rennie said after the match.
The news wasn't as good for fullback Tom Banks, who has already undergone surgery on his broken arm.
He is expected to be out for up to four months, having only just returned to the International stage after breaking his other arm during last year's Rugby Championship.
“It’s pretty serious,” Rennie said. “I haven’t had a chat to the medics about it but certainly won’t feature in the next wee while.
“He had total commitment to the kickoff and ended up high and flipped over the back of someone. No fault of the English but I’m gutted for Banksy because he’s worked so hard to get back and he’s had a great season, we’ll miss him.”
This will likely see Andrew Kellaway revert to the back, having produced a starring performance in Banks' absence.
Meanwhile, Cooper will undergo further scans on his calf after he was a late withdrawal.
Cooper pulled out during the warm-ups, with Noah Lolesio stepping up and guiding the hosts home.
“There was a reason why he was on the bench. He’s performed really well for the Brumbies. He’s trained really well in the last couple of weeks and there was a lot of confidence.,” Rennie added on Lolesio.
“He found out he was playing in maybe the last couple of minutes of our warmup and didn’t blink an eye. He was ready.
“(Nic) Whitey came over, obviously they’re club mates, and he was excited for him. We dragged James (O'Connor) out of the stand and got him stripped up and ready to go. Noah was excellent and his goalkicking under pressure again, we’ve seen that a lot of times, was really impressive.”
Rennie indicated after the match they will fight Darcy Swain's red card for headbutting, set to have their case heard on Tuesday evening.
