Corpas has filthy stuff when he's on with his fastball, sinker, slider combonation. He has a tendency to get wild at times and walk a few batters.
In the Spring, he allowed zero (yes zero runs) and has looked fantastic in his two appearances this season.
I think Corpas will eventually take over the 8th inning job this year and perhaps the closer's job next year if Fuentes departs.
Not sure how much value he has right now though, since he's only the 7th inning man at this point. Probably not worth a pickup unless it's a very large league.