Gameday has him as a 1.134 currently. Their rounding must be slightly different as I have him at 1.133. The difference between yours is in slugging: I have him at .714 SLG for the season so far. Almost as awesome as Jacksons 6/8 k/BB ratio.
Pretty high, I would have to imagine. Jackson may even press for a job on the big league squad in time to make Byrd available at the deadline. That would be LOVELY.