Kolar (forearm) was spotted with his left arm in a sling following Sunday's 26-14 loss to the Raiders, Kris Rhim of ESPN.com reports.
Kolar recorded three catches for 21 yards on three targets over 40 snaps on offense before a forearm injury forced him out of the contest in the second half. He was one of two Chargers tight ends to leave the game due to injury, as David Njoku (knee) also made an early departure. Head coach Jim Harbaugh declined to provide updates on Kolar and Njoku after the game, so until the team releases its first Week 3 injury report Wednesday, the statuses of both players will be muddled heading into next Sunday's matchup with the Bills.