Kittle is inactive for San Francisco's game Sunday against the Seattle Seahawks after being listed as questionable on the injury report. Kittle also missed the season opener at Chicago after getting hurt in practice earlier that week.
Kittle's injury leaves the Niners without two of their best offensive skill position players with running back Elijah Mitchell on injured reserve with a knee injury.
Kittle has been hampered by injuries in recent years. He missed three games with a calf injury last season, eight games in 2020 with injuries to his knee and foot, and three games in 2019 with a groin injury.
He had 71 catches for 910 yards and six touchdowns in 14 games last season. His 335 catches since entering the league in 2017 rank third among all tight ends in that span, and he is second with 4,489 receiving yards.