Justin Langer is poised to make some brutal selection calls that will shape Australia's Ashes squad but Usman Khawaja's hamstring injury remains a source of concern.
Langer has confirmed there are three or four spots up for grabs in Australia's 16-man squad and the final auditions will start on Tuesday, when the nation's best 24 players square off in Southampton.
Selectors are expected to name the Test squad after day four of the contest, which doubles as the tourists' only tune-up for the five-Test series that begins on August 1 in Birmingham.
Khawaja isn't taking part in the intra-squad game but Australia expect the hamstrung batsman, who suffered his injury on July 6 in what proved a costly World Cup loss to South Africa, to return at Edgbaston.
Coach Langer and chairman of selectors Trevor Hohns' dilemmas are complex and concurrent.
They are giving strong consideration to including Alex Carey as a reserve keeper but that would come at the cost of an additional batsman, quite possibly Joe Burns or Kurtis Patterson.
Burns and Patterson both posted tons in Australia's most recent Test.
Jon Holland was expected to be picked but selectors may opt for a legspinning allrounder ahead of a back-up tweaker, having been impressed by Test incumbent Marnus Labuschagne's productive county stint with bat and ball.
The selection puzzle is rounded off by a fierce battle between Peter Siddle, Jackson Bird, Chris Tremain and Michael Neser over one spot in a squad certain to feature guns Pat Cummins, Mitchell Starc, Josh Hazlewood and James Pattinson.
"There is a couple of bowling positions up for grabs, probably a couple of batting positions," Langer said.
"There will be a lot of discussion about whether we have an extra spinner ... an extra wicketkeeper.
"It's going to be brutal ... there are going to be some disappointed guys. There are going to be some really jubilant guys, some being on their first tour."
The headaches, mainly created by Steve Smith and David Warner's return from suspension, please Langer but the same can't be said of Khawaja's troublesome hamstring.
Langer was initially upbeat the 32-year-old might feature in the Southampton selection showdown.
"He was really close. You've seen him running, he's starting to hit," Langer said.
"You don't want him to be pushing it too soon and have it affect him the rest of the series.
"We'll have to wait and see what happens with the first Test match. Fingers crossed."
The four-day game between sides led by Tim Paine and Travis Head doesn't have first-class status, meaning selectors could hypothetically sub Khawaja into the contest later this week.
But Langer has made it clear he wants the contest to replicate a Test rather than a centre-wicket session as Australia hunt their first away Ashes series win since 2001.
The two camps have trained separately in recent days, while Paine has promised "Test-match intensity".