Ellsbury was so good over the last month of 2007 and then in the post-season that people got this unrealistic idea that he was going to jump right into the MLs and hit .330, with 80 SBs and score 130. And incredibly he actually got off to a start through the couple of months or so that would have put him close to later two numbers. He was near the league lead in runs scored at that point.
But as usually happens word got around about some holes in his strike zone, mainly jamming him, and he also hurt his left wrist making a diving catch and had a very bad middle of the season. Then he got hot again at the end, probably making some adjustments to how he was being pitched, lifting his average 13 points in the month of September. In all it was a very streaky year for him, great at the beginning, lousy in the middle, then great again at the end. But overall it was a very good rookie season. He nearly broke the RS single season SB record (54, I think) in spite of the terrible middle of the season, when he went something like a month with barely one steal.