SANTA CLARA — Kyle Juszczyk, an instrumental factor in the 49ers’ fourth-ranked rushing attack, is out the next four to six weeks with a knee sprain, the team announced Tuesday.
Jusczczyk sustained a sprained medial collateral ligament in his left knee while making a lead block for Matt Breida in the third quarter of Monday’s 31-3 blowout of the Cleveland Browns.
The 49ers (4-0) do not have another true fullback on their roster so they will have to adjust accordingly into mid-November. They play their first NFC West game Sunday at the Los Angeles Rams (3-2).
Jusczyzk, a three-time Pro Bowler, was enjoying arguably his finest season to date, and his lead blocks paved the way for a rushing attack averaging 126.