Thursday’s round of the Sheffield Shield is set to be the most pivotal in the competition’s 124-year history.

After losing 20 wickets for 246 runs in their series-surrendering innings and 80 run loss to South Africa in Hobart, Australia 13-man squad, sans the fast bowlers, have been sent back to first-class cricket to re-apply for their Test spot.

Bupa Support Team Head Coach Darren Lehmann said after play that only four players – captain Steve Smith, deputy David Warner, and new-ball pair Mitchell Starc and Josh Hazlewood – are certain starters for the third Test at the Adelaide Oval in nine days’ time.

Opener Joe Burns and middle-order batsmen Adam Voges and Callum Ferguson scored seven runs between them in the second Commonwealth Bank Test, while off-spinner Nathan Lyon went wicketless and wicketkeeper Peter Nevill missed a stumping and contributed only nine runs.

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“There'll definitely be change,” Lehmann said.

“The guys have got to play Shield cricket. By the end of the Shield game we'll have a squad for you.

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“I thought Hazlewood was great, Starc's getting back to his best and then you've got Smith and Warner.

“Outside of that everyone's got to make some runs and take some wickets.

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“It's a really important four days of Shield cricket.

“The lads are really keen to get out of here and get ready to play that game and prepare the best they can.

“(Existing) spots, performances are going to count, but you've got to have an eye to the future as well, it's trying that juggling act.”

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Only fast bowlers Hazlewood, Starc and debutant Joe Mennie will not play in the Shield, which features NSW taking on Victoria at the SCG, Queensland hosting South Australia at the Gabba, and Tasmania travelling to Perth to face Western Australia.

With collapses of 10-86, 10-85 and 8-32 already this summer, skipper Smith has called for batsmen in Shield cricket to “jump out of the pack” and put consistent runs on the board.

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In two rounds so far, 12 batsmen have posted first-class centuries, with Tasmania Tigers skipper George Bailey’s unbeaten 142 the season-high score to date.

Three players have scored 200 runs or more already this season – Victoria’s Marcus Harris (267 at 89), Bailey (259 at 86.33) and NSW Blues youngster Kurtis Patterson (222 at 55.50), while other strong candidates include Australia A captain Peter Handscomb, Redbacks skipper Travis Head and middle-order bat Jake Lehmann, WA’s Cameron Bancroft and Blues left-hander Nic Maddinson.

Whoever is chosen, whether it be a new crop of players or the existing line-up seeking redemption, Smith wants his men to show some grit and ticker.

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"I need players that are willing to get in the contest and get in the battle and have some pride playing for Australia, some pride in the Baggy green,” Smith said.

“That's what I need.

“At the moment it is not good enough, I am quite sick of saying it to be honest with you.

“It's happened five Tests in a row now, we've lost five in a row and for an Australian cricket team that is humiliating and I am embarrassed to be sitting up here in this position.”

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In those three monumental collapses, Australia crumbled in 29.3 overs in the second innings in Perth, 32.5 overs in the first innings in Hobart, and 19.5 overs on Tuesday.

Perhaps more than runs, Smith is looking for his men to occupy the crease, and it starts on Thursday in Sydney, Brisbane and Perth.

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"(We want them to) try and spend some time out in the middle and score some runs,” Smith said on what he wants to see in round of the Shield from Australia’s batsmen.

“It's not happening at the moment, so we've got to try and find a way to get better and spend some time in the middle and I guess concentrate on some of the things that I've talked about to the team.

“That's being able to be resilient, spend long periods out in the middle and get some big scores and put some big partnerships together.”

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While the batting is under the microscope, both Lyon and Nevill will turn out for NSW against Victoria where the main contenders for their respective positions will also feature.

Australia’s three most recent specialist Test spinners – Blues Lyon, Stephen O’Keefe and Victoria’s Jon Holland will square off, while Nevill will go head-to-head with ODI gloveman Mathew Wade.

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“We've got to make sure we go in the right direction for Australian cricket because at the moment we haven't been, so we've got to win some games,” Lehmann said.

“We've got to stop the rot to start with and play some good cricket again.

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“It's a really good chance for all the players who are playing Shield cricket again to put their hand up.”

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