SAN FRANCISCO - AUGUST 22: Glen Coffee #29 of the San Francisco 49ers runs against the Oakland Raiders during a preseason game on August 22, 2009 at Candlestick Park in San Francisco, California.  (Photo by Jed Jacobsohn/Getty Images)

A little over a year ago, Glen Coffee put together an eye-catching performance in preseason and some pundits believed that he could emerge as a solid complement to Frank Gore in the 49ers’ backfield.

That, of course, was before Coffee unexpectedly announced his retirement on Friday.

The San Francisco Chronicle is reporting that Coffee is calling it quits despite this being just his second year in the league. He was battling with rookie Anthony Dixon in camp, but head coach Mike Singletary noted that Dixon still had a long ways to go to leapfrog Coffee on the depth chart. Plus, Singletary has given Coffee high marks thus far, making his decision to retire/quit even stranger.

Singletary has developed a reputation over the last couple of years for running a tough camp, but that can’t be the only reason Coffee decided to pull the plug on his career this soon. After all, he got through Singletary’s camp as a rookie last year just fine.

That said, you never know what a person is going through until you’ve walked a mile in his or her shoes. Maybe Coffee has lost the passion to play or maybe he’ll regret his decision in a day and return to the practice field. Many young players struggle with being away from their friends and family and maybe Coffee is just going through a rocky time right now. Relatively speaking, he’s still just a kid.

Whatever the reason, it’s certainly a surprising development. The 49ers are still in good shape at running back with Gore, Dixon and Michael Robinson, but that doesn’t mean make Coffee’s decision any less shocking.