PHOENIX — Marshall Faulk's decision was easy after spending last year working for the NFL Network: At 34, his body is more suited for a television studio than for the rigors of playing running back.

After sitting out last season because of a knee injury, Faulk officially announced his retirement yesterday. He's ninth on the NFL's career rushing list, 33 yards behind Jim Brown, who at one time was the standard for the position.

Faulk, the 2000 NFL MVP, is fourth in combined yards from scrimmage with 19,154 yards and his 6,875 yards receiving are the most ever among running backs.

"Just being around the game last year, I realized how much I love it," Faulk said. "But my health is everything. And I didn't want to return if I couldn't get through a full season. It all came together when a close friend asked me 'How many 34-year-old running backs are there?' "

Faulk starred at San Diego State, where he rushed for 386 yards and seven touchdowns in his first game, and led the nation in rushing as a freshman.

He was the second pick overall in the 1994 draft by Indianapolis and was offensive rookie of the year that season.

He was traded by the Colts to St. Louis in 1999, and the Rams won the Super Bowl after the 1999 season. In 2005, Faulk rushed 65 times for 292 yards.