What RPs do you have available in your league, as FAs, waiver, and/or on the DL? FYI, Brandon League is set to become Seattle's closer again. Craig is a great hitter but he's an injury risk. Even if he does stay healthy, don't expect him to keep up the pace he has set for the games he has played.
What other players do you have available (pitchers, hitters)?
If you can afford the loss in saves, it's an easy decision. Pittsburgh won't blow teams away too often so there will always be save opportunities. I also don't think that he'll maintain his pace on saves just given the team he plays on. The Pirates are surprising many who knows if they'll be in contention to win as many games as they have been winning.
Straight up, I like the deal. Craig will give you versatile with his multiple-position eligibility, especially if you have any injuries. I also don't believe in "paying for saves", if at all possible, which is what the other guy will be doing. Just like you picked up Wilhelmsen (and will likely have to drop him soon), you should be able to find saves on the wire in a 10-team league. And hopefully Santos returns sooner than later.
Send the forum some more info so all options can be explored.
I doubt the other guy will be giving up more for Hanrahan...he's likely selling Craig based on his injury-risk. I think Jackson would be a safer bet...but I like a healthy Craig more...with both healthy...Craig will get you more HRs (most likely) and Jackson will get you more steals...both will hit well.
10-team mixed keeper league (15 keepers), H2H - 1 Win R/HR/RBI/SB/AVG/OPS/W/CG/SHO/SV/K/ERA/WHIP/QS
C - S. Perez
1B - A. Rizzo
2B - J. Kipnis
SS - T. Tulowitzki
3B - A. Beltre
OF - M. Trout, A. McCutchen, B. Harper
UTIL - J. Upton, E. Hosmer, A. Cabrera, EMPTY
DL - G. Stanton, K. Youkilis N/A slot: J. Profar
PITCHERS: (Lineup: 4 SP, 2 RP, 2 P)
SP - S. Strasburg, A. Wainwright, G. Gonzalez, M. Moore, K. Medlen, H. Iwakuma, S. Miller, W. Miley, A. Cobb, J. Garcia, H. Ryu, T. Cingrani, J. Hammel
RP - A. Chapman, A. Reed, J. Henderson, J. Tazawa, H. Bell