Kennedy's Liner Notes

Ian Kennedy of the Arizona Diamondbacks held batters to a .227 batting average this season, the tenth lowest BA allowed in the National League this season.  He gets there in a very unusual way, however, giving up a ton of line drives.

Kennedy 2011	Pct. In Play	MLB Average
Line Drives	20.2%	18.2%
Ground Balls	39.8%	46.9%
Fly Balls	40.0%	34.9%

Line drives tend to turn into hits, so when a pitcher gives up a higher than average number of liners, his batting average tends to come in at the high end.  Could batters simply be hitting their line drives right at the Arizona fielders?

Kennedy 2011	BA Allowed	Percentile Rank
Line Drives	0.740	38%
Ground Balls	0.190	89%
Fly Balls	0.228	78%

Not really.  Ian allows a .740 BA on his line drives, which is above average.  Only 37 percent of qualifying pitchers perform worse.  Where his fielders really help in on grounder and flies.  His batting averaged allowed on those type of balls in play is among the best in the league, more than compensating for his high line drive rate.  Only 7.7% of his fly balls go for home runs against a league average of 9.5%.  Since the fly balls that don't go out of the park tend to come down in the gloves of fielders, Kennedy gets another boost there.

You can also see that in his slugging percentage allowed:

Kennedy 2011	Slug Allowed	Percentile Rank
Line Drives	0.976	39%
Ground Balls	0.207	89%
Fly Balls	0.630	72%

His line drives go for power, but his fly balls generate a below average slugging percentage.

Watch out for Kennedy next season.  His .301 batting average on balls in play is well below league average.  If the defense behind him worsens, or a few more fly balls reach the seats, his ERA will end up back in the high threes.