Birk contemplated retirement for a couple of seasons, especially after 2011, but eventually opted to come back for one more run at a Super Bowl. I bet he's glad he decided to return.
He can now ride off into the sunset knowing his career ended in a Super Bowl victory and that he still has his health so he can enjoy the rest of his life with his family.
The retirement certainly doesn't come as a shock to the Ravens after encouraging him to return following the playoff loss in New England. The Ravens signed him to a three-year contract at the time, but knew it would likely be a year-to-year deal as to whether he would come back for another season. When the Ravens won the Super Bowl, it seemed likely that Baltimore had seen the last of Birk in a uniform.
He signed with the Ravens back in 2009 and spent four seasons in Charm City after a stellar career in Minnesota.
With Birk retiring, the Ravens will save more than $2 million against the salary cap for next season. It's likely that Gino Gradkowski, a rookie in 2012, will replace Birk as the team's new center. The Ravens drafted Gradkowski knowing that Birk's time in Baltimore would be coming to an end in the near future, once again showing that they were prepared to move on without him.
While Birk played extremely well this year, his retirement allows the Ravens to get much younger at the position while also saving significant money. With Lewis and Birk both retiring, the average age of one of the NFL's oldest teams should drop significantly heading into 2013.
The Ravens will now have over $17 million of cap space to work with once Ray Lewis officially retires. Joe Flacco is likely to take up basically all of that extra cap space when he signs his new deal, though the team is hopeful they can structure it in a way that keeps as much money freed up as possible for the 2013 season.
It's also likely the team will make a couple of cuts and restructure a few contracts to open up additional salary cap space. Vonta Leach seems to be one of the popular names on the chopping block while guys like Anquan Boldin and Jacoby Jones may be offered contract extensions in exchange for a small pay decrease in 2013.
It will be interesting to see if Birk opts to say in the area. He has previously talked about how much he enjoys living in Baltimore and has become a big part of the community. He is often praised for his charity work and was considered one of the good guys on the team, especially when it came to talking with the media.