Miller, 25, was picked sixth overall by Detroit in the 2006 amateur draft and was dealt to Florida as part of the big Miguel Cabrera/Dontrelle Willis swap in December 2007. Miller was seen as arguably the biggest piece (along with Cameron Maybin) of the six-prospect package that Florida acquired for their stars, but the left-hander has struggled to become a consistent major league hurler. In 79 career games, 54 of them starts, Miller has a 5.84 ERA and a 7.2 BB/9 rate. Miller was out of options with the Marlins and could've been non-tendered, but the Red Sox were clearly willing to take a chance on a young pitcher who still has a high ceiling.
Richardson is also a 25-year-old southpaw originally chosen in the 2006 draft, though Richardson's pick came in the fifth round. Also like Miller, Richardson has struggled with control issues — in 16.1 major league innings, Richardson has recorded 15 walks. His control has been better (4.4 BB/9 rate) in the minors, plus he has a K/9 ratio of 10.0 over his five minor league seasons. Richardson has pitched exclusively out of the bullpen for the last two years and the Marlins were known to be looking for relief pitching this winter.