Claimed off waivers from the Angels last week, the right-hander pitched just two-thirds of an inning for Bob Melvin's club, surrendering a single along with two fly ball outs.
A fixture in the Angels' bullpen last season, amassing a 3.00 ERA, 9.3 K/9 and 3.3 BB/9 across 54 innings, the 27-year-old Australian pitched just two and a third innings for the Halos this year -- giving up four runs -- before finding himself on the waiver wire for the first time.
Out of options, Thompson must clear waivers before he can report to his minor league assignment with Oakland.
Thompson expressed via Twitter his thoughts on the move:
Lost for words everyone, but thanks to all the A's fans you guys really welcomed me and made it feel like a great place to play— Rich Thompson (@Chopper_54) April 25, 2012
The A's have called up 29-year-old right-hander Jim Miller to take Thompson's place on the roster. Miller has just 14 innings of big league experience between the Orioles and Rockies, but has struck out 13 in that short time.