Former Vikings center and Cretin-Derham Hall graduate Matt Birk announced his retirement Friday morning during an appearance at a school near Baltimore.

"I have absolutely nothing to complain about and a lot to be grateful for," Birk said.

The Baltimore Sun reported: "His retirement was hardly a surprise as the Harvard graduate had pledged to go year-to-year with his decision on whether to return. In the final weeks of the season, he acknowledged that his mind was pretty much made up, but unlike his teammate Ray Lewis, he was going to wait until after the year to make it official."

Birk, 36, played for the Vikings from 1998-2008 before leaving to sign with the Baltimore Ravens. The Harvard alum will be walking away from the final two seasons on a three-year contract.

You can read the full report here.