Juszczyk spent the past eight seasons with the 49ers, making the Pro Bowl every single year, including a First-Team All-Pro selection in 2023 and Second-Team All-Pro honours in 2024.
"I know I'm not done," said Juszczyk. "I'm definitely not done playing. I've seen zero regression. I think especially, I mean, you can turn on the last two games and please show me where I've regressed, so I have no plans of stopping."
The 33-year-old veteran was drafted in the fourth round of the 2013 NFL Draft by the Baltimore Ravens, where he spent the first four seasons of his career before moving to San Fran.
Juszczyk, nicknamed "Juice", has been hailed by many as the best fullback in the league for the past decade alongside current Ravens fullback Pat Ricard.
His departure will mark yet another for the 49ers who have seen plenty of their players leaving this free agency, including the following:
(WR) Deebo Samuel - Washington Commanders (traded)
(CB) Charvarius Ward - Indianapolis Colts
(S) Talanoa Hufanga - Denver Broncos
(LB) Dre Greenlaw - Denver Broncos
(OT) Jaylon Moore - Kansas City Chiefs
(RB) Elijah Mitchell - Kansas City Chiefs
(QB) Josh Dobbs - New England Patriots
(G) Aaron Banks - Green Bay Packers