The 49ers placed Hargrave (triceps) on injured reserve Saturday, Nick Wagoner of ESPN.com reports.
Hargrave partially tore his triceps during the 49ers' Week 3 loss to the Rams, and head coach Kyle Shanahan relayed Monday that the injury likely keep the veteran defensive tackle out for the rest of the regular season, per Nick Wagoner of ESPN.com. With Hargrave sidelined, Jordan Elliott is set to serve as San Francisco's starting defensive tackle alongside Maliek Collins, though Elliot is listed as questionable for Sunday's game against the Patriots after injuring his foot during Thursday's practice.