well, era isn't necessarily the best stat to look at for relievers.
but, he doesn't give up a lot of hits (.237 baa over his career), and while his walk rate isn't great, his k rate is quite good.
so, basically, he doesn't give up a lot of hits, and even though he walks guys he has the ability to make hitters miss.
is he a great reliever? no. but i think people overestimate how easy it is to find reliable bullpen arms, which frasor is. he's steady.. like jays said, a good 7th or 8th inning guy who has proven that he can serve as a decent backup closing option (in 04 and 09 -- the only two years in his career he was used as a closer for etzended periods -- he is 28/33, which isn't great but isn't bad either).
i like the pick up. they got a solid reliever for shit all.