Kosuke Fukudome wasted no time winning Cubs' fans hearts in 2008, hitting a game-tying three-run home run in his major league debut, and blistering the baseball in his first month in the majors. At the end of his first April, he was hitting .327/.436/.480 and looked like a star.
The rest of the season didn't go quite as well. Fukudome hit .241/.340/.355 from May through September, showing little power and earning a late season benching. In 2009 we saw much of the same. In his 89 April plate appearances Fukudome hit .338/.461/.592, an improvement even over his hot April 2008. The rest of the way he hit .245/.360/.393, again a bit better than 2008 but still a disappointment after another torrid start.
He’s again off to a good start -- he's hitting .297 -- yet Cubs fans have been conditioned to expect much worse once the calendar turns to May. Why has he hit so much better in April than the rest of the year?
It is tough to assign cause to such a small sample, however, we can see a discrepancy in his batted ball types in April compared to the rest of the season. In the first month of the year, Fukudome hits the ball in the air and drives it with some regularity, as seen in the graph below. It shows the percentage of flyballs to each zone divided by total balls in play, with the colors showing slugging percentage -- the redder the better. As you can see, he turns into a groundball machine as the season wears on. And after driving the ball to right field seven percent of the time in April, that number drops to three percent the rest of the year.
If you’re more of a numbers person than a graph person, Fukudome’s career GB percentage in April is 41 percent, compared with 50 percent the rest of the year.
At a glance, it might seem like hitting ground balls isn't all a bad thing. Ground balls, after all, produce hits at a greater rate than fly balls. But that only touches on one dimension of hitting -- and even then, it's not a particularly compelling argument. Last year in the National League ground balls produced a .234 batting average, while fly balls produced a .224 average. (Line drives, the third type of batted ball, had a .728 average.) But slugging percentage on fly balls is considerably higher than on grounders. NL hitters slugged .595 on fly balls last season, while they slugged just .255 on ground balls. It’s pretty hard to hit a groundball over the wall.
While some hitters can benefit from hitting the ball on the ground, Fukudome does not profile as one of them. He possesses the power to hit near or in the middle of the order, having hit 31 homers for the Chunichi Dragons in 2006. However, he doesn't take advantage of this power once the calendar flips to May. He's off to a strong start again, and he has kept the ball in the air at a greater frequency than in his past two seasons. Maybe it's Fukudome's year, but until he shows the ability to hit fly balls and line drives in the later months, don't expect an improvement.
Joe Pawlikowski is a writer for FanGraphs.