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This is, of course, a supplement to Dave's post from yesterday. Dave observed that the early returns on Casey Kotchman's adjusted swing are positive, as the historically extreme groundball hitter has spent the better part of April putting more balls in the air.
Kotchman's groundball rate so far is 39.1%, over 46 balls in play. For his career, he comes in at 52.3%. Quite the striking change. I got curious to see if this sort of stretch is unprecedented. Has Kotchman ever before demonstrated this sort of ability to keep the ball off the ground?
I spent a little while going through Kotchman's game logs, and the answer is, yes, he has. As best as I can tell, he's had stretches like on five separate occasions:
8/14/05 - 9/11/05: 47 balls in play, 18 grounders (38%)
6/5/07 - 7/3/07: 52 balls in play, 20 grounders (38%)
9/5/07 - 9/23/07: 48 balls in play, 15 grounders (31%)
4/14/09 - 5/3/09: 55 balls in play, 19 grounders (35%)
6/18/09 - 7/3/09: 49 balls in play, 18 grounders (37%)
It's discouraging to see that he's done this before, because Kotchman's always been a groundball hitter, meaning these stretches were anomalies. However, if you're looking for a reason to believe that this current stretch is different from the previous ones, note that, over those past five stretches, Kotchman hit ten home runs over 321 trips to the plate, while so far in 2010 he's hit three in 57, which could be a sign of a good development. It's also worth noting that the fly ball stretches where he showed the most power were in 2005 and 2007, when Kotchman was productive despite ending up as a groundball hitter overall.
Ultimately, we can't be conclusive about anything. We have too small a statistical sample and too little knowledge of swing mechanics to be able to say whether what Kotchman's been doing will continue. For the time being, though, I'd say you should proceed with cautious optimism. We don't know if Casey Kotchman will be a productive hitter going forward, but better to be prompted to ask this question by early success than by early disappointment.