Middlebrooks, a third baseman, has been in the Sox system since 2008, when he started with Class-A Lowell. In 2011, Middlebrooks played at three levels within the organization, starting with Lowell (.333/.400/1.167) and moving to Double-AA Portland (.302/.345/.520) and Triple-A Pawtucket (.161/.200/.268).
Lin, on outfielder, has been with the organization since 2007. Last season, Lin split time between Double-A Portland (.268/.373/.333) and Triple-A Pawtucket (.235/.325/.293), playing in 119 total games.
Britton is a left-handed pitcher and started with the club in 2008 with Class-A Lowell. In 2011, Britton spent the entire season with Class-A Salem, where he struggled mightily, posting a 1-13 record with a 6.91 ERA, 89 strikeouts and 55 walks in 26 games.