A frustrating start to the new NFL season has continued for the San Francisco 49ers after they had to place star cornerback Richard Sherman on injured reserve.

Per widespread reports, the Niners made the roster move on Wednesday after assessing a calf injury suffered by the five-time All-Pro selection.

Sherman is subsequently unavailable for at least three weeks, ruling him out of upcoming contests against the New York Jets, New York Giants and Philadelphia Eagles.

That is a significant blow to the team beaten in February's Super Bowl LIV, with the Niners also losing their season opener 24-20 at home to NFC West rivals the Arizona Cardinals on Sunday in a tough outing for quarterback Jimmy Garoppolo.

The Niners' number one corner Sherman played in 74 of their 78 defensive snaps in that game, giving up just one catch for nine yards on two targets.