The Royals acquired Pearson from the Astros on Wednesday in exchange for Max Martin.
Pearson had been designated for assignment by Houston, but he will now join a 40-man roster in a new organization. The hard-throwing righty holds a 3.60 ERA, 1.40 WHIP and 16:12 K:BB in 20 innings in the majors this season. Pearson does not have any minor-league options remaining, so he will join the Royals' bullpen.