Barely a month after being appointed interim captain of South Australia and then following up with a match-winning century at the SCG, Tom Cooper finds himself out of the team and once again fighting to save his first-class career.

Cooper, who was cut from the West End Redbacks' list prior to the previous summer but earned a reprieve with a full contract at the start of this season, has been dropped for SA's final match of the JLT Sheffield Shield season against Western Australia at Gliderol Stadium from tomorrow.

And Redbacks coach Jamie Siddons has signalled that the onus is now on the 31-year-old to find greater consistency in his batting as SA begin to mull over their player requirements for next season, given they currently sit in bottom position on the Shield ladder.

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Cooper, who has played more than 40 limited-overs internationals for the Netherlands (where his mother was born), was named to lead the Redbacks against Victoria last month when regular skipper Travis Head was playing for Australia and his deputy, Callum Ferguson, was absent through injury.

But despite scoring the only century (105 not out) of a hard-fought seven-wicket win over New South Wales in SA's next match, the experienced right-hander posted just 89 runs from his subsequent four innings and has been replaced by 25-year-old Alex Ross for the final Shield match.

SA coach Jamie Siddons said today that while Cooper's omission did not spell the end of his tenure with the Redbacks that has yielded 69 Shield matches and more than 4,000 runs (at 34.71), it was a clear indication that more was expected of senior players after a disappointing 2017-18 campaign.

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"It's not the end of him by any stretch, he made a hundred three games ago and that was awesome, but just the overall contributions weren't enough to hold his spot," Siddons said today.

"He's a senior player in our group, a bit like Ferg (Ferguson), we expect him to carry the group when the rest aren't going well.

"He (Cooper) has a tendency to go missing for three or four games in a row, and we can't afford that with a senior player.

"We need to make sure we're getting good scores all the time.

"He knows that, and he's got to find a way to come back and do it."

The issue that Cooper faces in trying to state his case for a new contract before list management meetings begin in coming weeks is that his Premier Cricket club (Port Adelaide) are not involved in finals matches that begin this weekend in Adelaide.

Adding further complexity is Siddons' endorsement of Ross, who earned his place with a century against Tasmania in last week's Toyota Futures League fixture, as a potential answer for the middle-order batting woes that have regularly haunted SA this season.

"Ross has been making good second XI runs including a hundred last week, so we thought it was time to give him a crack and probably a good, long run at it," Siddons said.

"(He's) a good player."

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The other conundrum for Cooper, and for any batter who finds themselves struggling in the second half of the summer against the English-made Dukes that swings significantly, is that club cricket utilises the locally manufactured Kookaburra-brand ball that does not present the same challenges.

As a consequence, Siddons claims that coaches at Shield level are having to radically re-think the way they tutor middle-order batters coming through the ranks, and increasingly expose them to a new ball at training to enable them to develop a technique more closely resembling an opener's role.

"Every batsman is like an opening batsman because it (the Dukes ball) goes around corners for the whole day, not just 10 or 15 overs," Siddons said today.

"Your number six and seven generally come in against an older ball that doesn't do much, but now they're like opening batsmen and we have to train them and coach them differently.

"They have to face new balls in the nets a lot more.

"So it's a massive challenge for the batsmen, especially when you get out of form – it's hard to get back.

"I love the Duke because it's a challenge for the coaches, it's a challenge for the batsmen and it makes the bowler in the game.

"With the Kookaburra, at times, it's a very flat game and lots of runs are scored.

"(But) if we're going to use it and for them (emerging players) to get better at it, we've got to use it in club cricket for a start, I think."

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The Alcohol. Think Again Western Warriors, currently just half a point ahead of bottom-placed SA on the Shield ladder and contemplating their first wooden spoon since 1963-64, have included left-arm quick Joel Paris in their 13-man squad.

Paris, who played two ODIs for Australia in 2016, has been battling a series of quadriceps injuries that required surgery and has not played a Shield match for more than two years.

The 25-year-old returned to cricket with the Perth Scorchers towards the end of the KFC Big Bash League but has been building up his bowling workloads in Perth's grade competition over recent weeks.

Both teams will finalise their starting line-ups at tomorrow's coin toss.

Squads

South Australia: Travis Head (c), Alex Carey, Callum Ferguson, Jake Lehmann, Conor McInerney, Joe Mennie, Kane Richardson, Alex Ross, Jake Weatherald, Nick Winter, Daniel Worrall, Adam Zampa

Western Australia: Ashton Turner (c), Ashton Agar, Will Bosisto, Hilton Cartwright, Liam Guthrie, Josh Inglis, Matt Kelly, Simon Mackin, Joel Paris, Josh Philippe, D'Arcy Short, Marcus Stoinis, Jonathon Wells