ESPN's Adam Schefter reported the injury will sideline Kittle for eight weeks.
It's a major loss for a 4-4 Niners team in last place in the NFC West. San Francisco also faces a lengthy absence for quarterback Jimmy Garoppolo, per Schefter:
The 27-year-old Kittle suffered the injury during Sunday's loss to the Seattle Seahawks after missing time earlier this season because of a knee sprain and a bone bruise. He has been fairly durable in his career and sat out just three games in his first three seasons.
Kittle is arguably the best tight end in the league and was a Pro Bowler the last two years with more than 1,000 receiving yards both times. He helped lead San Francisco to the Super Bowl last season with 85 catches for 1,053 yards and five touchdowns.
The Iowa product has 37 catches for 474 yards and two scores in 2020.
While the 49ers don't have anyone nearly as explosive as Kittle to play tight end while he is sidelined, look for Charlie Woerner and Ross Dwelley to see more time. It also wouldn't be surprising if the offense relied even more on its rushing attack.