San Francisco 49ers LG Alex Boone went down with a knee injury in the third quarter of play against the Browns in Cleveland. Marcus Martin entered the game to replace him.


The medical staff appeared to be looking at Boone's right knee/leg. He was able to walk off of the field under his own power.


Boone went into the locker room with the 49ers medical staff for further observation. He has been reported as out for the remainder of the game.


Boone grew up in the Cleveland area and played college football at Ohio State.