Morales, 27, opened the year on the DL due to a bulging disc in his lower back. His 2012 season ended in late August thanks to shoulder fatigue. He has also had forearm, hamstring and other shoulder issues in the past.
In nine starts and 28 relief appearances for Boston last year, Morales went 3-4 with a 3.77 ERA and 1.23 WHIP. He did strike out 76 batters in 76 1/3 innings but also surrendered 11 home runs. The lefty pitched quite a bit better in relief (3.23 ERA) than he did as a starter (4.14 ERA).
The Red Sox acquired Morales, who ranked the eighth-best prospect in the game according to Baseball America before the 2008 season, from the Rockies in a minor trade in May 2011. In parts of five years in Colorado, he went 7-11 with a 4.83 ERA in 147 1/3 innings while occasionally flashing brilliance.
Right-handers Alex Wilson and Alfredo Aceves seem most likely to be sent to Triple-A Pawtucket to clear a roster spot for Morales. Wilson has pitched well enough, posting a strong 2.65 ERA despite an ugly 1.59 WHIP in 17 innings. Aceves was recently recalled and owns a 8.20 ERA in 18 2/3 innings to go along with his circus act.
Morales will join Andrew Miller and Craig Breslow to give Farrell three left-handed relievers. Given his experience as a starter, Morales can be used as something more than a lefty specialist.