Kyle Juszczyk plays an unheralded but essential role in Kyle Shanahan’s offense, and now the 49ers may have to add the 35-year-old fullback to their growing list of missing weapons.

Juszczyk could be sidelined for “a couple of weeks,” according to ESPN insider Adam Schefter, after initial tests showed that he hyperextended his knee on a hit from Broncos cornerback Jahdae Barron.

Juszczyk left the 49ers’ 24-14 win over the Broncos on Sunday and didn’t return after Barron barreled into his knees to bring him down on a 16-yard reception on their first play of the fourth quarter.

Initially, Shanahan said after the game that the 49ers believed Juszczyk had sprained his knee. 

Schefter reported that he will undergo further tests Monday, which could rule out damage to any ligaments. Shanahan is expected to provide an update Monday afternoon on his weekly conference call with reporters.

While Juszczyk was recently in the spotlight for his juice-drinking touchdown celebration that drew the ire of the league office, the Harvard alumnus is better-known for having a more precise understanding of Shanahan’s system than anybody besides possibly quarterback Brock Purdy.

The 10-time Pro Bowler was the first major acquisition the 49ers made after hiring Shanahan in 2017, and they’ve only had to play without him seven times in almost 10 full seasons since.

Juszczyk has earned All-Pro honors each of the past three seasons, including first-team nods in 2025 and 2023.

With the hits the 49ers have already taken at receiver, Juszczyk has taken on an even more important role in the passing game as one of Purdy’s few remaining trusted targets.

The first-down reception was his second catch Sunday, totaling 28 yards, and he also had a second catch to go along with his touchdown in their Week 2 win over the Dolphins.

Heading into a treacherous Week 5 matchup against the Seahawks in Seattle, the 49ers offense could be without Juszczyk, Demarcus Robinson, De’Zhaun Stribling, Ricky Pearsall and Christian Kirk. 

Nobody has been able to slow down the Shanahan-Purdy connection so far, but it might be a different story against the “Dark Side” defense without one of its most versatile weapons.