The Chargers placed Njoku (fibula) on injured reserve Wednesday.
Njoku will be sidelined for at least the Chargers' next four games after sustaining a fibula injury in Sunday's 26-14 loss to the Raiders. Fellow tight end Charlie Kolar (forearm) was able to avoid placement on IR but has already been ruled out for the Chargers' Week 3 contest in Buffalo, leaving Oronde Gadsden as the top option on the depth chart heading into that game.