The San Francisco 49ers are working this week on ways to adapt to the loss of their Pro Bowl fullback, Kyle Juszczyk. The team expects him to miss four to six weeks with an MCL sprain. Although, Juszczyk hopes the timeframe will actually be shorter.

The 49ers enter Week 6 with the No. 1 rushing offense in the NFL, and Juszczyk's blocking skills have been a key component in the run game's success. The group is averaging 200 yards per game this season and 5.2 yards per attempt.

Juszczyk is also a significant part of the offense's pass protection and keeping quarterback Jimmy Garoppolo on his feet. The fullback has earned a Pro Football Focus pass-blocking grade of 82.9 this season, his highest grade since joining the 49ers, and his 83.9 overall grade is the highest of his NFL career and leads all fullbacks by a significant margin.

Garoppolo was asked what it will be like not having Juszczyk in the lineup for possibly a month or more.

"Yeah, it'll be different," the quarterback responded. "But, you know, the coaches, they've been working hard getting the game plan ready. We've got to go out there and execute it, so whatever it is, it is."

That plan is still getting installed, and the 49ers have three days of practices this week to learn and perfect it before Sunday's NFC West showdown with the Los Angeles Rams.

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Added Garoppolo: "It's football. The guys are going to get hurt. Next man up, and we'll play after that."

The problem is that there is no "next man up." Juszczyk is the only fullback on the roster of a team that relies heavily on the position. The 49ers haven't brought in a temporary replacement and, if they haven't done so by now, likely won't — at least, not for this weekend's game.

"Juice does so much for this offense," Garoppolo continued. "He just, the versatility, he does things that most fullbacks can't do. He's catching passes out of the backfield, diving for catches while also cutting a D-end on the backside. It's little things like that. It'll be important for us to get that just with other people."

It will be interesting to see how head coach Kyle Shanahan tweaks the offense to work around Juszczyk's absence. With the fullback out for an extended time, the 49ers may rely more on tight end George Kittle's blocking skills.

"For a guy who just broke the tight end record last year for most yards and everything and then to come in and block the way he blocks, you just don't see that every day in the NFL," Garoppolo said of Kittle. "You've got to tip your hat to him, and happy birthday shout out to him, too."

Oh yeah, we remembered, too.