The Chargers signed the 25-year-old former Wallabies flyer on a three-year NFL deal in April as a tight end, after Petaia impressed in the International Player Pathway.
He made a late cameo in the Chargers' first pre-season game last week, but didn't register a statistic.
On Friday (AEST) Petaia was waived and replaced by fellow Australian and former schoolboys rugby teammate Thomas Yassmin.
Sydney product Yassmin played college football at Utah and spent last season as an IPP athlete on the Denver Broncos' training squad.
The Chargers on Saturday opted to place Petaia on their injured reserves list, ahead of the 53-man roster deadline this month.
AAP understands the hamstring injury is only minor and that Petaia, no stranger to soft-tissue complaints in his rugby career, Â is treading cautiously to avoid a long-term issue.
Well aware of the NFL's brutal approach to contracting, Petaia is understood to be unperturbed and assessing his options.
NFL clubs can recall eight players from their injured list to play each season, although with fellow tight end Yassmin assuming the extra, designated IPP spot, it's unlikely the Chargers would dedicate a 53-man roster spot to Petaia.
Atlanta, Cleveland and Kansas City had initially expressed interest in Petaia, who could be taken as an IPP athlete by a club yet to sign one.
The Queensland Reds, where Petaia debuted as an 18-year-old, gave him their blessing to chase an NFL career, and have remained in close contact with the talent.
But there is no formal arrangement tying Petaia to the Super Rugby club, should he seek a return to the 15-man game.
Injuries, including hamstring issues, regularly interrupted his 31-Test career for the Wallabies.
Yet he still became the youngest Australian to play at a Rugby World Cup.
He played at a second World Cup, before giving up the chance to face the British and Irish Lions and rolling the dice on an NFL shot late last year.
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