Jon Lester has retired after a 16-year career with the Red Sox (2006-14), Athletics (2014), Cubs (2015-20), Nationals (2021), and Cardinals (2021).
Lester, who turned 38 last Friday, was a member of three World Series champions: the 2007 Red Sox, 2013 Red Sox, and 2016 Cubs.
It's kind of run its course. It's getting harder for me physically. The little things that come up throughout the year turned into bigger things that hinder your performance.
I'd like to think I'm a halfway decent self-evaluator. I don't want someone else telling me I can't do this anymore.