The Red Sox have designated reliever Edward Mujica for assignment.
The 30-year-old righthander is 1-1 with a 4.61 ERA in 11 games and 13⅔ innings this year, with 8 strikeouts and 3 walks. Opponents are hitting .294 with a .345 OBP and .490 slugging mark (three homers) against him.
While the corresponding roster move isn’t clear, the fact that the Red Sox had righthander Matt Barnes appear out of the bullpen for Triple A Pawtucket Wednesday in Toledo — having been scratched from his scheduled Thursday start — suggests the Sox may be laying the groundwork to add him as a potential swing-and-miss power arm to their late-innings mix.
Barnes, 24, worked around a pair of singles to log a scoreless eighth inning Wednesday. He threw 22 pitches, 15 for strikes, while striking out a batter and getting three swings and misses. He worked primarily at 93 miles per hour and finished his night by stranding a pair of runners with a 94-m.p.h. fastball for a called third strike.
“I think we’re just trying to prepare him to potentially help the major league team,” said Sox general manager Ben Cherington. “There’s no long-term determination on what he is, but we certainly believe he can be a starter in the long run, but we’re just simply trying to prepare him to help the major league team.”
The Sox have been shuffling Barnes between the bullpen and rotation since spring training. The team looked at him as a potential relief contributor in Grapefruit League action before getting him stretched out in the rotation for the start of the Triple A season.
He made a pair of Triple A starts before getting summoned to the big leagues, where he contributed two scoreless innings April 25 against the Orioles. He was shipped back to Pawtucket after that outing and made one start (allowing one run and striking out seven in four innings) before Wednesday.
The Sox typically express discomfort with bouncing their pitchers between the rotation and bullpen. At this point, the idea of having Barnes enter a game in the late innings for Pawtucket would seem to suggest that the Sox have decided that his contributions in the near term will indeed be in relief, quite possibly for the duration of 2015 — even if his long-term future has not yet been fixed.
Castillo in a groove
Back in the PawSox lineup as the designated hitter after a day off Wednesday, Rusney Castillo went 2 for 5 with a double in a 6-5 win over Toledo, his second straight multihit game. On Tuesday, he went 2 for 4 with a walk, snapping an 0-for-11 slump . . . Former Sox catcher Jarrod Saltalamacchia agreed to a minor league contract with the Arizona Diamondbacks after being released by the Miami Marlins last week.
Julian Benbow of the Globe Staff contributed to this report. Alex Speier can be reached at email@example.com. Follow him on Twitter at@alexspeier.