Curt Young signed a one-year deal as pitching coach of the Oakland Athletics, the team announced on Friday. Young spent seven seasons there before joining the Red Sox last November.
Under the eye of Young, Boston's pitching staff posted a 4.20 ERA, which ranked 22nd in the majors. The team's 71 quality starts ranked 28th in baseball, while the team WHIP of 1.31 ranked the Sox 16th.
Young had one year remaining on his contract with Boston.