ANAHEIM -- The A's optioned left-hander Eric Surkamp to Triple-A Nashville and transferred right-hander Henderson Alvarez to the 60-day disabled list, retroactive to March 25, to clear roster space for Saturday starter Dillon Overton, who was promoted from Nashville to start against the Angels in his Major League debut.
The A's still need a starter for Wednesday's Interleague matchup with the Giants, and the club has penciled in rookie Sean Manaea, who made 64 pitches over 3 2/3 innings in a rehab start Friday with Class A Advanced Stockton.
Manaea (forearm) has been on the DL since June 14 and the lefty is eligible to be activated Wednesday.
"He felt great, so it's good news for us," A's manager Bob Melvin said Saturday. "That's what we've been targeting, but we'll see how he feels in the next couple days."
Surkamp is 0-5 with a 6.98 ERA in nine starts with the A's this year. He received a no-decision in Friday's win over the Angels, and was charged with four runs on five hits in 3 2/3 innings. Surkamp has worked fewer than five innings in seven of his nine outings and opponents are batting .327 against him.
Alvarez began the season on the 15-day DL and has been shut down a second time in his rehab from last year's right shoulder surgery. He's been visiting this week with Dr. James Andrews, who performed the surgery last July.
Overton, 24, went 7-0 with a 1.40 ERA over his last seven starts with Nashville. Oakland's No. 9 prospect, Overton will be the third A's pitcher to start in his big league debut this year. A second-round pick in 2013, Overton is the first player from Oakland's '13 Draft class to reach the Majors, despite missing his first professional season after undergoing Tommy John surgery.