Holders England may be on the brink of retaining the Ashes after a crushing 347-run win in the second Test at Lord's left them 2-0 up in the series with three to play but that match saw Kevin Pietersen suffer a calf injury that has left him doubtful for the Manchester clash.
England chiefs made it clear who they have in mind to replace Pietersen if the South Africa-born shotmaker is unfit by requesting Nottinghamshire's James Taylor 'guest' for Sussex this week against the tourists.
Taylor played two Tests against South Africa last year but didn't make the England squad for the tours of India and New Zealand.
However, the diminutive batsman has been in good first-class form this season, scoring 824 runs in 15 County Championship appearances, including an unbeaten double century against Sussex in June.
QUICK SINGLE: Sussex v Australia, Day One Highlights
With Australia batting first Friday in the three-day game at Hove, Taylor will hope he gets a chance to prove himself against international opposition on Saturday.
But the dangers of putting too much emphasis on one match as a selection guide were obvious Friday when Australia reserve wicketkeeper Matthew Wade, trying to force his way into the Test side as a batsman only, was out for a duck.
The 23-year-old Taylor has been keen not to get ahead of himself, telling reporters earlier this week: "I'm hopeful that KP (Pietersen) will be fit to play and, as it stands, I'm preparing to play in the three-day game for Sussex and nothing more
"I'm not back in the Test side yet but I'm pleased to be a step closer to it and I've always dealt with situations like this by concentrating on the game in hand and refusing to look too far ahead."
Pietersen, in an indication of the treatment work he has undertaken in a bid to regain full fitness, told his Twitter followers: "Might try getting in the car this am and when turning on the ignition, say the words, "gym for rehab.." Surely it will drive me there.."
Pietersen's 2013 has been beset by injuries, with a knee problem forcing him home early from the tour of New Zealand in March and then ruling him out of the return series against the Kiwis and the subsequent Champions Trophy tournament.
He made 64 in the second innings of the first Test but suffered two failures at Lord's.
As well as Taylor, England's selectors will be keeping a close eye on Sussex left-armer Monty Panesar as they consider whether to play a second spinner alongside Graeme Swann on an Old Trafford pitch which, while it last staged a Test in 2009, remains renowned for taking turn.