Tonges (knee) was placed on injured reserve Wednesday.
Coach Kyle Shanahan told reporters after the opening week win that Tonges' injury "[did] not look good," and the 49ers' placement of the tight end on IR affirms that. The team did not give a timeline for Tonges' return, and Ian Rapoport of NFL Network notes that this is an MCL injury. The 49ers signed tight end Jack Stoll to the practice squad in a corresponding move.