Does Playing Shallow Work?

One of the newest data points now being tracked by Baseball Info Solutions is the direction that every defensive player moves in order to field a ball in play. Directions are broken into nine possibilities in a grid that looks like this:

There’s a lot that can be done with this new data to analyze defense. One thing we can use this for is to analyze the value of an outfielder playing shallow, especially a center fielder. One of the long-standing theories in baseball is that some of the very best center fielders can play shallower than others because of their ability to get a great jump on a ball hit over their head and because of their tremendous speed to track it down. By playing shallow they can turn a lot of short flies and liners into outs that would otherwise have fallen in for base hits. And the only deeply hit balls that get past them would have gotten past them anyway regardless of where they played.

That’s the theory. With this new data from BIS we can look into this more closely. Here’s what we did. We started with the 35 center fielders in baseball with the most playing time this year and looked at how often they went back on a batted ball and how often they broke in. The concept is that if a center fielder has to go back more often than others he is playing shallower. The player who has played the shallowest center field this year, based on this method, is the Nationals’ Denard Span. He has gone back on a batted ball 212 times out a total of 503 plays. That’s 42 percent of the time. At the other extreme, the deepest center fielder is Aaron Hicks who’s gone back 115 times out of 369 plays (31%).

Here are the ten players who have played the shallowest center field in baseball by this method:

These six players play deep, having gone back on a ball less than a third of the time:

The next thing we did was to group the players into two groups. The Shallow group contains the 10 regular center fielders who have played the shallowest center field in baseball this year. The All Other Regulars group includes the other 25 regular center fielders. Now we can look at our defensive Plus/Minus System to measure the number of plays made or not made, and the number of bases gained or lost on those plays. The number of bases gained or lost will help us account for the fact that it’s worse to give up a double or a triple than it is to give up a single.

The Shallow group as a whole saved 13 bases making plays compared to an average center fielder on balls hit less than 300 feet. The All Other Regulars group cost their teams nine bases on shallow hit balls. That’s a difference of about 22 bases on plays with shallow hit balls. Surprisingly, it’s a very small advantage.

On deeply hit balls (over 350 feet), the Shallow group cost their teams 67 bases on deeply hit balls. The All Other group saved their teams 104 bases. That’s a difference of 171 bases. That’s huge.

If you look at Plus/Minus Runs Saved, where we translate the bases saved or lost into runs, you get:

Overall, playing shallow saves 13 runs while playing deep saves 97 runs.

Theory busted!

OK, that may be a little strong. It is possible that there may be that rare gifted center fielder who can play shallow and still make the plays going deep. And, I’m sure there are other studies that can be conducted to try to corroborate, or even possibly refute, this result. But this data suggests that trying to play extremely shallow is not a good strategy overall.