Adam Schefter of ESPN (h/t ESPN's Nick Wagoner) reported the deal includes $10 million in guaranteed money.
Juszczyk confirmed the deal on Instagram: "So incredibly thankful to be apart of this organization for 5 more years! Thank you Faithful for the continuous support! Looking forward to showing that the juice is always worth the squeeze"
The newly paid fullback was the most-used player at his position in the NFL in 2019. Juszczyk saw the field for 36.5 percent of the Niners' offensive snaps in 2019 per Football Outsiders, just edging out Minnesota's C.J. Ham (34.7 percent) for the league lead.
The result: 246 total yards and a touchdown, but that hardly quantifies just how important the 29-year-old is to one of the top offenses in football.
NFL analyst Brian Baldinger went through Juszczyk's play in the NFC Divisional Round against the Vikings and pointed out how much of an impact a modern fullback has without getting any carries:
Juszczyk can be used as a decoy, a pass-catcher, a runner and a blocker. At 6'1", 235 pounds, he's as tough to move out of the way in the trenches as he is impossible to slow down once he gets momentum on the run. Few guys in the NFL can fill that role as effectively as Juszczyk. It's why he's a five-time Pro Bowler and why the 49ers are willing to bring him back on such a notable contract.
He appeared in all 16 games during the 2020 campaign and finished with 266 total yards and six touchdowns.
While San Francisco struggled to defend its NFC title and went 6-10, it will look to bounce back in 2021 with one of its most important offensive players.