The 29-year-old underwent arthroscopic knee surgery shortly after the team's second preseason game when he felt soreness in the area. He will be eligible to return from the IR after eight games.
Tom Pelissero of NFL Network reported Saturday there was no timetable for a return but that he wasn't expected back before the team's Week 4 bye.
"We're putting Matt on injured reserve to give him time to fully rehab the knee," general manager Marty Hurney said. "We decided to make the move now so he's eligible to come back after eight games."
Kalil is heading into his second year with the Panthers after signing a five-year, $55.5 million contract in 2017, per Spotrac.
He started all 16 games last season, the fifth time in six years he was able to complete a full season. His only missed time came in 2016 when a hip injury limited him to just two games for the Minnesota Vikings.
While there have been question marks about Kalil's consistency on the field, Joe Person of The Athletic reminded people the damage this injury can cost:
Taylor Moton, a second-round pick in the 2017 NFL draft, will likely replace Kalil as the team's starting left tackle to begin the season.