Last year was the best year of Ben Zobrist's professional career. Not only did he tear it up in Durham to the tune of .366/.471/.577/1.048 (wOBA of 135) in 20 games (making it impossible for the Rays to keep him in AAA), but also had his most successful tenure in the bigs. Zobrist was very, very good in his 62 games with the big club this summer; his slash line was .253/.339/.505/.844 with 12 HRs. He was third on the team in wOBA (.367) of all players with more than 200 PAs.
So, the question is "Why was Zobrist so much more effective this year, than in years past?" Well, the simple answer is a lot more of his fly-balls left the yard. In his two previous big league stints (52 and 31 games, respectively), Zobrist's HR/FB% were 4.3% and 3.6%. This year his HR/FB% was 17.4%. He essentially went from Jason Bartlett territory to Evan Longoria. Is this change legit? Looking at Zobrist this year, he did look bigger. He looked stronger. How much difference can we expect that to make, though?
Another reason why Zobrist was more successful was he exhibited the patience that made me like him as a minor leaguer when we traded for him. His BB-rate had never been below 12% in the minors, and it was 3% and 5.2% during his two previous times up. This year it was a more typical 11.2%. He swung at less pitches out of the zone (17.8% versus 26.7 and 23.3%) and swung at more pitches in the zone (61.8% against 59.7% and 60.9%). As a result, he made more contact and firmer contact.
So, Zobrist's great year was a mix of some-part luck and some-part improvement or skill. The question we will likely have answered in the future is "How much was each?"