Who should play center field for the Mariners?

Jerry Dipoto was on a mission this offseason. Over the last five years, the Mariners’ outfield defense has been the worst in the majors by a wide margin, no matter which metric you choose to look at. What was once territory roamed by Death to Flying Things had become a place where hits fell from the sky regularly. Simply adding league average outfielders to the team would have improved the team’s outlook. Dipoto went three steps further and added two center fielders to the roster to flank Leonys Martin.

Beyond simply upgrading the defense, Dipoto was actively assembling a roster that maximized the value of an elite outfield. At the SABR Analytics conference a few weeks ago, Dipoto directly addressed this concept: “We have a pretty fly-ball-centric pitching staff. That’s our pitching staff, so how do we maximize the value of a fly-ball pitching staff, and an environment that should be beneficial to a fly-ball pitcher with an outfield… We wanted to create a new paradigm for our club that was more built on defense and the ability to go run it down.”

With three players who played more than 50 games in center field last season on the roster, an argument could be made for any of the three to suit up there this season. Jerry Dipoto and Scott Servais have already made their optimal outfield alignment clear—Martin in center, Jarrod Dyson in left, and Mitch Haniger in right. Still, that shouldn’t stop us from looking at these three players and at least discussing what their ideal alignment might look like.

Last week, I dove into the new catch probability numbers released by MLB.com and Baseball Savant. In short, using Statcast data, catch probability tells us the odds that any given batted ball will be caught by a fielder. Every opportunity is assigned a difficulty based on hang time and the required distance to make the play. This new metric gives us a general idea of which fielders are making more difficult plays more often, relative to league average catch rates.

Below is a table with the Mariners three starting outfielders and their relevant defensive stats over the last two years combined.

His sample size is incredibly small but the data shows us that Mitch Haniger can really go get it. In his brief time in the majors with the Diamondbacks, he made four plays more than expected which extrapolates to a ridiculous 27 plays above average per 150 opportunities. That’s probably not representative of his true talent but it’s clear Dipoto targeted him for more than just his promising bat.

The real discussion for Mariners fans has been between Martin and Dyson. If you read my post last week, you’ll know that Martin has been criminally underrated by the traditional advanced defensive metrics like Ultimate Zone Rating or Defensive Runs Saved. Dyson’s numbers haven’t suffered from that same kind of discrepancy. No matter which way you slice it, Dyson has been one of the rangiest outfielders in baseball the last two years.

If we were just using the advanced defensive metrics to inform our argument, Dyson would win in a landslide. But catch probability introduces a new wrinkle. The difference in plays made per 150 opportunities between Martin and Dyson isn’t really that big. Even when we dig down into their individual difficulty buckets we see that Dyson is a little better at converting more difficult opportunities but gives up that advantage on easier opportunities.

Let’s see if we can discern anything further from their defensive profiles using their defensive spray charts. Below you’ll find spray charts that show their most difficult catches (<75% catch rate) and the hits they probably should have caught (>25% catch rate). Dyson played all three outfield positions last season so there are a few extra points of data on his chart.

Leonys Martin:

Jarrod Dyson

Both Martin and Dyson show an ability to make difficult catches in front of them, but it seems like Martin has a bit of an advantage here. Martin also looks like he’s able to cover more ground in left-center field. When comparing players like this, we have to remember that not every player’s opportunities are equal. It’s possible that Dyson just didn’t have many opportunities to run down a batted ball in left-center field.

Traditional baseball wisdom would tell us that the outfielder with the strongest arm should play in right field in an effort to cut down runners advancing to third base. But in any given season, a center fielder will see about 30% more batted balls than a right fielder. That doesn’t necessarily translate to 30% more opportunities to throw out a runner, but if you’ve got a weapon like Leonys Martin’s right arm, why not maximize his opportunities to use it.

Based on the statistics and their defensive profiles (both range and arm strength), it seems like the argument between Martin and Dyson is closer than it might seem. If that’s the case, then we should start to consider some of the other implications. Martin has about 160 innings of experience outside of center field—111 in right field and 56 in left field. Asking him to make a position change might not be the best idea in an outfield where clear communication is going to be paramount. Dyson has experience at all three outfield positions—though he’s spent the majority of his time in center field. Furthermore, Dyson’s range profile above looks like it’s perfectly suited for a spacious left field like Safeco’s.

I’m willing to bet that playing one over the other in center would end up being a wash over a full season. If Martin ends up on the disabled list this season, the Mariners won’t be left without options in center like they were last season. Even Haniger, Guillermo Heredia, and Ben Gamel appear to be capable center fielders if needed. That alone is a luxury this team hasn’t enjoyed since Franklin Gutierrez and Ichiro were patrolling the outfield.