The Red Sox acquired right-hander Clayton Mortensen from the Rockies. (AP)

The Red Sox’ main motivation for dealing shortstop Marco Scutaro was to clear his $6 million payroll in order to make a run at addressing other areas of need, most likely their rotation. Even so, the team acquired a pitcher who could provide them with a depth option for either the rotation or the bullpen in right-hander Clayton Mortensen.

Mortensen, 26, has a 4-8 record and 5.12 ERA in 24 big league games (13 starts) over the past three seasons. A sandwich pick of the Cardinals in the 2007 draft, Mortensen was traded to the A’s as part of the deal sending Matt Holliday to the Cardinals in 2009 and then dealt by Oakland to the Rockies for minor league pitcher Ethan Hollisworth last year. He showed some promise with Colorado over the course of two and a half months in the majors last year, going 2-4 with a 3.86 ERA in 16 appearances (six starts). Mortensen was 2-3 with a 4.15 ERA as a starter and had a 3.42 ERA in relief. The sinkerballer had command issues, walking 24 and striking out 30 in 58 1/3 innings.

One major league talent evaluator described the right-hander as a sinker slider pitcher with a build that allows him to project as a starter, but his stuff has seemingly plateaued, and he is likely to define himself either as a future back-of-the-rotation starter or a middle reliever given his grounder-inducing sinker and “fringy” secondary pitches.

Last offseason, Mortensen was rated the No. 14 prospect in Oakland’s farm system by Baseball America, which described him thusly: Read the rest of this entry »