After top-scoring twice against India A in Mackay last week, McSweeney was promoted to the top of the order against the same opposition so he could audition for the vacant opening spot in the Test team.
McSweeney started strongly, but was dismissed by Mukesh Kumar for 14 in the final session of day one at the MCG on Thursday.
The 25-year-old bats at No.3 for South Australia and had never opened at first-class level before.
But the way into Australia's XI for the Border-Gavaskar series is as Usman Khawaja's opening partner, with Steve Smith moving back to his preferred spot of No.4 this summer.
Australia A were 2-53 when rain forced stumps to be called early.
McSweeney's opening partner Marcus Harris (26*) remains unbeaten, with NSW teenager Sam Konstas (one*) surviving an unplayable opening delivery.
Marcus Harris is unbeaten on 26 overnight. (James Ross/AAP PHOTOS)
But Cameron Bancroft's hopes of a Test recall are all but over after he was out for three, continuing his dismal start to the summer.
Across seven first-class innings for Western Australia and Australia A, Bancroft has scored just 29 runs at 4.14.
Bancroft dominated for Western Australia during the past two Sheffield Shield seasons, but has lost form at the worst possible time.
Earlier, Michael Neser hobbled off the MCG with a hamstring injury only hours after ripping through India A's top-order to seemingly put himself back in Test contention.
The Queensland bowling allrounder made a mess of the tourists as they crumbled to 5-64 at lunch, after McSweeney won the toss and elected to bowl first.
But Neser (4-27) managed to bowl just two balls of his 13th over, before pulling up sore and walking dejectedly off the field only minutes before the tea break.
Michael Neser hobbles from the field mid-over, having ripped through the India A top order. (James Ross/AAP PHOTOS)
Neser won't bowl again for the rest of the match and will undergo scans on his left hamstring to determine the damage.
India A were bowled out for 161, almost entirely thanks to a brilliant unbeaten 80 from wicketkeeper Dhruv Jurel.
They collapsed to 4-11 during a chaotic first 16 balls of the match.
Neser was on a hat-trick in his first over after dismissing Abhimanyu Easwaran and Sai Sudharsan in consecutive balls.
Ruturaj Gaikwad survived the hat-trick ball, but fell in Neser's next over.
Neser is congratulated by teammates as he swept through the India A top order. (James Ross/AAP PHOTOS)
In between, Scott Boland removed KL Rahul, an option to play against Australia in the opening Test of the Border-Gavaskar series, for just four.
The wickets tumbled so quickly that the scoreboard at the MCG failed to realise Rahul had been promoted to open after he had initially been listed to bat at No.4.
Rahul was dropped for India's third Test defeat against New Zealand last week, arriving in Australia early to try and find some form for India A.
Boland spoke about Rahul on Tuesday: "He's obviously a world-class player, but he is someone we can hopefully get on top of pretty early and stay on top of him for most of the summer."
It only took three balls from Boland (1-22) - and four overall - to get Rahul out at the MCG.
Boland hasn't played for Australia since the 2023 Ashes, but will be in consideration for a call-up this summer should pace stars Pat Cummins, Mitchell Starc and Josh Hazlewood be unavailable.
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