Stoinis appeared in immediate discomfort after Ryan Burl played a shot back to him late in the innings on Friday and was seen consulting with medical staff.
Another veteran on the sidelines is the last thing Australia need given Josh Hazlewood (hamstring, achilles), Pat Cummins (back) and captain Mitch Marsh (testicles) are already out.
Australia will require all the batting firepower they can get if Stoinis, their top-scorer in their first match of the tournament, is sidelined from the run chase.
Tim David is at least back from the hamstring injury that had sidelined him since Boxing Day
Australia won the toss but missed pacemen Cummins and Hazlewood, with breakthroughs proving all too rare on against a Zimbabwe side that finished at 2-169.
Stoinis ended their 61-run opening stand and became the first Australian man with 50 wickets and 1000 runs in T20Is when Tadiwanashe Marumani (35) edged to Josh Inglis.
Cameron Green (1-6) struck with the first delivery he bowled finishing the injured Stoinis' final over, with substitute fielder Xavier Bartlett taking a catch behind the stumps to dismiss Burl (35).
But that was as good as it got for the Aussies, whose two strike weapons from the first-up win over Ireland - Nathan Ellis and Adam Zampa - went wicketless.
Ellis (0-34) and Zampa (0-31) at least managed to help Australia stem the bleeding after Burl went, with Zimbabwe scoring only four boundaries in the final four overs.
Matthew Kuhnemann spilt a tough chance in the deep that could have dismissed Brian Bennett on 53, but that was the only major opportunity Zimbabwe gifted their rivals that they failed to convert.
Opener Bennett, 22, finished as Zimbabwe's top-scorer with an unbeaten 64 runs from 56 balls.
Death master Ellis did well to concede only five runs in the first five balls of the last over, only for captain Sikandar Raza (25 not out) to belt him for the innings' only six on the last ball.
After a slow start, opening batter Marumani ignited the innings by giving Glenn Maxwell a taste of his own medicine, sweeping the allrounder for four on three occasions in his only over.
Not even Australia's T20I talisman Zampa was immune to punishment, clubbed for two boundaries in his own first turn with the ball.
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