The A’s announced on Monday that right-handers Simon Castro, Michael Brady and Josh Smith have all been assigned outright to Triple-A Nashville after clearing waivers. The moves give Oakland enough space to reinstate outfielder Dustin Fowler and righties Andrew Triggs, Paul Blackburn and Bobby Wahl from the 60-day disabled list. Castro, 29, totaled 37 innings out of the Oakland bullpen, working to a 4.38 ERA with 8.5 K/9 against 3.4 BB/9. Castro averaged nearly 94 mph on his heater, but as an extreme fly-ball pitcher that saw 14 percent of flies against him turn into homers, he also averaged 1.7 long balls per nine innings pitched. The journeyman righty posted a career-best 14.9 K/9 in 38 Triple-A innings this season but averaged five walks per nine, as well. He’s set to turn 30 next April.