Outside linebacker Terrell Suggs, who set a career-high with 14 sacks and set a team record with seven forced fumbles in 2011, finished second in the annual vote.
But it was also a career year for the versatile Rice, in his fourth year out of Rutgers.
The shifty tailback gained career-highs in rushing (1,364 yards) and receiving (704 yards) while scoring 15 touchdowns, obliterating his previous career high of eight scores set in 2009.
Rice's 2,068 total yards from scrimmage led the NFL. He also fumbled just twice all season.
Rice is in the final season of a four-year, $2.8 million contract he signed after becoming a second round draft pick in 2008, according to Spotrac.com.