Yesterday, Brewers beat reporter Adam McCalvy reported that Milwaukee would like new center fielder Carlos Gomez to keep the ball on the ground. At first blush, it makes sense. Gomez doesn’t have much power, so he’s unlikely to hit many home runs, and with his speed, he has the ability to turn routine ground balls into infield singles.
McCalvy also shares some of the numbers that led the Brewers to this conclusion:
Brewers researcher Karl Mueller provided the raw data. Throughout his career on balls put in play, Gomez is a .195 hitter on fly balls (261 put in play), a .631 hitter on line drives (123), a .268 hitter on ground balls (306) and a .446 hitter on bunts (102 put in play, 10 of which were sacrifices). Gomez’s high average on line drives is not surprising; the Major League average is typically about .700.
The cracks in the analytical armor start to show. Breaking down performance by batted-ball type is useful, but … batting average?
If we limit our focus to batting average, Gomez isn’t the only player who should hit more balls on the ground. In last year’s American League, average on ground balls was .240 against .223 for fly balls.
Of course, that isn’t the whole picture. Fly balls have advantages that go beyond batting average. Home runs, anyone? Again using last year’s AL average, slugging percentage was .260 on ground balls and .603 on fly balls. Which would you rather have?
The answer seems tilted heavily in the direction of fly balls, but that may not be the case for all hitters. Certainly you’d never teach Russell Branyan to become a slap hitter in order to improve his batting average, but for players—especially speedsters—who don’t hit for much power, maybe the increase in hits is worth a decrease in power.
Over the course of his major league career, Gomez has appeared to be one of that latter group of players. You can see the exact breakdown at baseball-reference, although the numbers differ a bit from Mueller’s.
What kind of player is he?
A batting average difference of .268 to .195 sounds huge, but there are some differences to keep in mind. As noted, Gomez isn’t going to slug .500 any time soon, but he does get his share of extra-base hits. In his career, in fact, he’s managed 12 home runs and 12 triples, along with 42 doubles, for an isolated power of .100. He’s only 23, so there’s hope that he’ll develop still more power. In fact, CHONE predicts that he’ll slug .390 this year for an ISO of .123.
In fact, if we glance at his 2005-07 minor league splits, we see a player with GB/FB splits closer to average. While his average was still higher on ground balls (.281 to .269), he slugged .554 on fly balls against only .288 on grounders. Gomez has many of the positive qualities that one associates with a speedy slap hitter, but we might be selling him short by shoehorning him into that stereotype.
Slugging percentage doesn’t tell the whole story either, but many of the other considerations are quibbles, or just end up canceling each other out.
For a player like Gomez, grounders give him an opportunity to reach on infield errors more often than the average player. (He has done so nine times in his career, which is actually a bit less often than the average player.) Sacrificing doubles for singles is a bit less painful for him than it is for others, since he is more likely than others to make up the extra base by stealing it.
On the flip side, even a speed demon like Gomez hits into double plays, and the more ground balls he hits with a runner on first, the more times he is likely to be doubled off.
So far, there’s an argument to be made on both sides. Gomez may well be the sort of player who would create more value by hitting more grounders.
The 800-pound gorilla in the room is the line drive. Up to this point, I’ve presented the argument as if Gomez makes contact and one of two outcomes results: a ground ball or a fly ball. But whether we’re using Mueller’s or baseball-reference’s numbers, there’s a third non-bunt outcome.
It’s not easy to hit a lot of line drives off major league pitching, but when hitters manage to do so, the results are fantastic. The average AL player last year had a .739 batting average and a 1.015 slugging percentage on liners. Gomez’s major league results are a .639 AVG and a .975 SLG, with line drives making up about one out of seven batted balls.
No matter how you slice the numbers, line drives are overwhelmingly a good thing. It seems obvious that whatever batting coaches teach their charges, it should never result in fewer line drives.
Given only a six-paragraph article from a beat reporter, it’s tough to know exactly what Ken Macha and Dale Sveum are trying to accomplish. If the goal is for Gomez to make more solid contact and avoid hitting pop flies, that’s great. Just about every player could benefit from that. If Macha and Sveum agree with McCalvy’s conclusion that “Gomez would be well-served by keeping the ball out of the air,” that’s another story.
Let’s look at the breakdown statistically. Gomez’s career wOBA on grounders is .286, on flies it is .230, and on liners it is .689. Converting into runs, every fly ball he turns into a ground ball is worth about 0.05 runs. Every line drive he trades for a ground ball costs his team about 0.25 runs—a sacrifice of five times as much as the benefit gained by each fly-turned-grounder.
The ideal outcome for Sveum might be to adjust the trajectory of all of Gomez’s batted balls downward. If some popups became fly balls, some flies became line drives, and some liners became ground balls, Gomez’s performance would probably benefit. I have no idea whether such a thing is possible.
What should be evident is that ground balls, even for a player of Gomez’s profile, are not such an unambiguous good. Maybe the Brewers are aware of the intricacies. It would be a shame to hold back a youngster developing moderate power and turn him into a more limited player than he needs to be.