Double A ?
Edit: Oh it says right here at Redsox.com
Exactly one month after re-joining the Red Sox and winning his first Major League start since overcoming cancer, Jon Lester was optioned to Double-A Portland on Thursday. Julian Tavarez will start in Lester's place on Sunday against the White Sox.
Lefty reliever Javy Lopez has been recalled from Triple-A Pawtucket to take Lester's roster spot.
The move was made primarily to give the Red Sox an extra lefty arm in the bullpen for their upcoming road trip to Chicago and New York. Both the White Sox and Yankees feature dangerous left-handed hitters.
Lester is slated to make just one start in the Minors, returning to Boston's rotation for a Sept. 2 start against the Orioles at Fenway Park.
After pitching well in that first start on July 23 in Cleveland, Lester (2-0, 5.67 ERA in six starts) struggled thereafter.
Why Portland and not Pawtucket for Lester? Red Sox PR spokesman John Blake said that Portland's rotation lines up better for Lester to stay on his regular day.
-Redsox.com