Laffey, 26, split last season between the Yankees and Mariners. In 47 games, he posted a 3.88 ERA and a 103 ERA+, but was very hittable and posted a poor strikeout-to-walk ratio of 30-to-21 in 53.1 innings. For his career, he has a 1.54 WHIP and a strikeout-to-walk ratio of 1.24.
Laffey is a classic lefty who has to rely on locating his pitches and changing speeds to avoid being knocked around. He has a fastball that ranges from the mid- to upper-80's and a changeup. He shifted to the bullpen after the 2010 season but didn't see much difference in his performance. He continued to walk too many batters for a pitcher with his underwhelming stuff.
It's hard to see where Laffey fits with the Royals going forward unless the team thinks he can improve against left-handed hitters. He certainly hasn't dominated against lefties in his career, as they've posted a .718 OPS against him in 519 plate appearances. The team has a bullpen full of pitchers who are much better options, and even more down in the minor leagues who would be better choices than Laffey.
However, he's more interesting than Chavez, who is two years older, isn't a lefty and has a 5.36 ERA in 143 career games. It's a mild upset that Chavez survived as a member of the 40-man roster as long as he did.