After missing practice on Thursday and Friday, 49ers running back Glen Coffee has unexpectedly retired. Matt Maiocco of CNS Bay Area first reported the news.

According to Maiocco, Coffee met with 49ers coach Mike Singletary this morning.

Coffee, who was selected in the third round of the 2009 NFL draft, only played one season in the NFL. The 49ers are expected to add another running back soon. Anthony Dixon and Michael Robinson are the 49ers only reserve running backs.

"Glen informed us this morning of his intent to no longer play the game of football. I respect that. I appreciate everything he has done for the 49ers. Whatever the issues are, I'm not going to go into all the other stuff," Singletary told reporters.