Lester will head to the team with baseball 's best record as the Athletics continue a stunning re-tooling of an already solid club .
Lester is the left - hander who keyed World Series titles in 2007 and 2013 .
Lester , the left - hander who keyed World Series titles in 2007 and 2013 , will head to the team with baseball 's best record as the Athletics continue a stunning re-tooling of an already solid club .