Raiders tight end Michael Mayer has missed the team's last two games and he will miss at least four more before he'll be able to return to action.

Mayer has been out of action for personal reasons and the Raiders placed him on the non-football illness list on Friday. Neither Mayer nor the team has provided any further information about the nature of his absence.

Mayer had four catches for 21 yards in the first three weeks of the season.

Rookie Brock Bowers is the No. 1 tight end for the Raiders. Harrison Bryant and John Samuel Shenker are the other players at the position.