Pena's struggles are flukey. The patience and power are still there, but he has an unsustainably low .219 BABIP.
BJ Upton is having a similar season to last year in both statistics and peripherals.
Zobrist's power binge i argued was a fluke last year, and it's seeming more and more i was right. He's a LD/GB hitter, so a 17% HR/FB was going to be hard to maintain. Lo and behold, the OBP and BA have stayed, but the power is basically gone. Keep in mind though, he has a .440 SLG% with a .357 BABIP, and if that normalizes, both the BA and SLG% could take a hit.
John Jaso's provided more with the bat in this short time than all of their catchers last year combined, so that's a plus.
Bartlett's been victimized by injuries, but Brignac has been useful.