David Pinto had a post up earlier regarding Jeter's new approach to hitting. Following up on that, check out his batted ball splits from the two previous seasons.
That .667 batting average on line drives ranked in the bottom 5% in all of baseball last season. Was Jeter just unlucky with his liners? There's always the issue of subjectivity when it comes to line drives. One stat reporter may see a hit as a line drive with elevation while another might see it as simply a fly ball. So you're going to get some variation there, and as a result Jeter's LD batting average might get hurt (or even helped).
But there's also the possibility that his line drives were simply not hit as hard last season. Liners are going to drop as hits more often than any other batted ball because they have less air time than fly balls and are thus far more difficult for fielders to make a play on. If Jeter's line drives did not have as much velocity as previous seasons (perhaps with less elevation), it could definitely have played a part in lowering that average. It will be interesting to see how his new swing (with the elimination of that big leg kick) affects his batted ball types this season.