The 5-foot-11, 200-pound second-round draft pick played in 15 games in his rookie season, carrying 10 times for 54 yards. He's expected to challenge for more carries with Steven Jackson now playing for Atlanta.
The Rams announced the suspension Friday. Pead is eligible to take part in all offseason and preseason practices and games.
Pead is the second Rams player suspended for violating the substance abuse policy. On May 22, second-year offensive lineman Rokevious Watkins was given the same penalty.