Smith announced his decision on Monday in just the latest blow to the 49ers this offseason.
Two other defensive stars have also retired in linebackers Patrick Willis and Chris Borland. Coach Jim Harbaugh is also gone, along with running back Frank Gore, guard Mike Iupati, receiver Michael Crabtree and cornerback Chris Culliver.
Smith played 14 seasons in the NFL after being drafted in the first round by Cincinnati in 2001. After seven seasons with the Bengals, he signed as a free agent in San Francisco and had his best success in seven years with the 49ers.
He was a defensive stalwart on a team that made three straight NFC championship games and played in one Super Bowl. Smith is a two-time All-Pro and a five-time Pro Bowler.
Updated May 18, 2015
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