Gray sustained the setback in the opening quarter of the clash at Richmond Oval, with the Power deciding not to risk the 33-year-old for the remainder of the match.
The Port Adelaide forward missed a handful of matches through the back-end of last season after requiring knee surgery, with Gray able to play out the final five matches of the Power's 2021 campaign.
His latest injury setback adds to the Power's growing list of players currently occupying the club's casualty ward, with Charlie Dixon (ankle), Orazio Fantasia (knee), Trent Dumont (knee) and Sam Powell-Pepper (hamstring) among those hindered this pre-season.
Robbie Gray being rested after hurting his hamstring on the field 🤕
— Fox Footy (@FOXFOOTY) March 5, 2022
Port Adelaide will open their home and away season at the Gabba against Brisbane on Saturday, March 19.
Gray enters his 16th season with the Power in 2022, having played 255 matches since making his debut in 2007.