More and more, the 49ers' decision to draft recalcitrant (and unsigned) wide receiver Michael Crabtree rather than offensive tackle Michael Oher with the 10th overall pick in April's NFL Draft is looking like a personnel blunder.
Chronic back problems ended Smith's football career – and dashed the 49ers' hopes that they had found a starting right tackle to take over for standout Joe Staley, who is taking over at left tackle.
Smith, a nine-year veteran, did not accompany the 49ers to Irving, Texas for today's preseason contest against the Dallas Cowboys, and he did not disclose a reason for staying behind.
The 49ers signed Smith, 31, hoping to add badly needed depth at right tackle and as a backup at both tackle positions. But he did not perform well at training camp physically. The team's projected starter at right tackle, Adam Snyder, sustained a right knee strain and was ruled out of the Cowboys' game.
Coach Mike Singletary announced Friday that Barry Sims, an eight-game starter last season, would start at right tackle against Dallas. Jacob Bender and undrafted rookie Alex Boone provide what little depth the 49ers have at the tackle position.
The Santa Rosa Press Democrat reported Friday that Smith had told the team he planned to retire, but the 49ers did not confirm that until Saturday.
"I would like to thank Marvel for this service to the 49ers organization over the last several months," Singletary said in a statement Saturday. "Marvel and I have spoken, and I know this was not a decision he took lightly. We appreciate that he came to us when he did with this decision, and we wish him well in the next chapter of his life."
Smith, an Oakland, CA native, was a second-round pick of the Pittsburgh Steelers in 2000 out of Arizona State. A Pro Bowl selection in 2004, he started 108 of 111 career regular season games and all 10 postseason games in which he appeared. Smith was a member of two Super Bowl champion Steelers' teams.