Oakland A's recall RP Angel Castro, option RP Arnold Leon

The Oakland Athletics appear to be swapping out back-end relief pitchers after the A's bullpen was forced to go 7⅓ innings on Thursday after throwing a bullpen game yesterday. Right-handed pitcher Arnold Leon was optioned to Triple-A Nashville and Angel Castro recalled to Oakland in his place as the A's get set to face the San Francisco Giants this weekend.

Castro, 32, made four appearances for the A's in May totaling three innings as they cycled through their bullpen options. He allowed six hits but just one earned run, a solo home run. In Triple-A, Castro has a 3.40 ERA in 42⅓ innings, striking out 31 and walking 12.

Arnold Leon, 26, pitched 3⅓ innings for the A's on Thursday. He allowed three hits and one earned run while striking out two and walking none.

With the A's expected to recall Chris Bassitt to start on Saturday in place of the injured Jesse Hahn, this is most likely a one-day visit for Castro.