The Oakland Athletics designated pitcher Rich Thompson for assignment on Wednesday, just days after he was claimed off waivers.
In addition to Thompson, the Athletics also optioned pitcher Fautino De Los Santos to Triple-A Sacramento and brought up pitchers Jarrod Parker and Jim Miller from the minor league club.
Thompson appeared in one game for Oakland after coming over from the Angels last Friday. He threw two-thirds of an inning on Monday against the White Sox.
De Los Santos, meanwhile, had pitched to a 3.00 earned run average in six relief appearances for the Athletics this season, but had not retired a batter in any of his last three outings.
Parker was 1-0 with a 2.18 ERA in four starts for Sacramento, while Miller was 0-1 with two saves and a 3.00 ERA in eight relief appearances for the Pacific Coast League team.