Giordano left the game in the first quarter after intercepting Brandon Weeden for 24 yards. Giordano also had one tackle against the Browns.
Raiders head coach Dennis Allen told Vic Tafur of the San Francisco Chronicle that injuries were a factor in the game bu the team needs to "find ways to persevere."
Adams was hurt in the second quarter after replacing starter Ron Bartell following a 44-yard touchdown pass from Weeden to rookie Josh Gordon which gave the Browns a 10-0 lead.
Adams has eight tackles and one interception in 12 games this season. Mitchell has 19 tackles in 12 games this season and was also knocked out of the game.
After a 3-4 start to the year, the Raiders have lost five games in a row to fall to 3-9 this season.