I like John's analysis, but this isn't the worst deal in the world. The bottom line ? is whether you think McCann is sophomore jinxed. I don't.
McCann hit 6 HRs in the first half of last season. Second half? 18. Now, you know why the other guy trading with you wants McCann.
Essentially, you are trading two guys who are liable to do better in both SBs and HRs... so you are arguably helping the other team rather than yourself. Hanley is liable to get 50-60 SBs. McCann will get 20+ HRs. So, analyze this trade with that in mind. McCann will likely give you 18+ more HRs in a HR scarce position, and this is really important.
**I re-read your post... because you have Ichiro and Reyes, you don't need to make this deal. I wouldn't. Victor Martinez is great and arguably less of a gamble than McCann... BUT, McCann was the second best fantasy catcher in all of baseball last year according to PlayerTrack. His second half last year makes him worth the gamble the rest of the way this year, in my opinion.
TRADE Hanley, Ichiro, or Reyes for 40+ HR power. It is that simple. Reyes will give you top of the line trading power... he looks to steal 75+, though.