The Rays Have the League’s Best Outfield Defense

The Rays just traded for Peter Bourjos, a soon-to-be 30-year-old worth zero WAR over the past two seasons. The Rays are giving up basically nothing, because just a couple months ago, Bourjos signed a minor-league contract with a go-nowhere team. You don’t want to read a blog post about Peter Bourjos. I don’t want to write a blog post about Peter Bourjos. But he’s one part of a bigger-picture collection — the Rays are assembling another fantastic outfield.

Another fantastic defensive outfield, I should say. Heaven knows if Bourjos is going to actually hit. As you know, it all begins with Kevin Kiermaier, who might be the best defensive outfielder in the world. And the Rays are no strangers to having good defense out there; they were fifth by both DRS and UZR last season, and they were first by both measures the season before. Kiermaier is good enough to carry a group by himself. This year, though, he won’t have to do that.

Here is the Rays’ projected team depth chart. You see projected components, besides just projected player and positional WAR. Scroll down to the outfield positions. The outfielders, combined, project to be 18 runs below average at the plate. Not good! But they also project to be 26 runs above average in the field. That’s a little over-simplified, because it gets messy when you have outfielders playing multiple positions, but this works to get us in the right neighborhood. And I should say that defensive projections are inherently conservative. But it was that easy to get an idea on the Rays. It was just as easy to get an idea on everyone else. Here is all of MLB, in terms of combined outfield defensive runs above or below average:

It’s Tampa Bay in first by what is, relatively speaking, a sizable margin. The gap between the Rays and the Red Sox is 7.1 runs, which happens to be the same as the Twins’ combined projection, and the Twins rank here in ninth place. By spread, the Orioles are 1.6 standard deviations below the average. The Red Sox are 1.6 standard deviations above the average. The Rays are 0.7 standard deviations above the Red Sox. The projections are far from perfect, and players can become unpredictably hurt or unpredictably bad, but the Rays outfield profiles as a batted-ball death trap.

I led with Bourjos. Everyone knows about Kiermaier. There’s also Colby Rasmus, Steven Souza Jr., and Mallex Smith, to say nothing of Corey Dickerson. Rasmus is expected to begin the year on the disabled list, which is part of the reason why Bourjos was acquired in the first place. There are layers upon layers of depth in center field. And Statcast also likes what the Rays have put together.

A few weeks ago, Catch Probability was introduced. I don’t know how much of this I have to go over again, but as a quick refresher, they can calculate a batted ball’s odds of being caught, based on hang time and distance from where an outfielder began. To this point, the metric is still a bit too simple; direction isn’t yet folded in, and neither is the added difficulty of trying to make a play by the wall. But those tweaks shouldn’t change numbers dramatically. And based on all the outputs we’ve seen on individual outfielders, I’ve been able to calculate catches made above or below expected catches made. It’s an estimate, but take it for what you will.

I looked at all the outfielders last year who had at least 50 opportunities, according to the Baseball Savant leaderboard. There were 109 of them. I put all the plus/minus estimates over a common denominator to allow for easy sorting. Here are outfielder rankings of interest:

• Kevin Kiermaier: 3 (out of 109)
• Peter Bourjos: 8
• Mallex Smith: 19
• Steven Souza: 36
• Colby Rasmus: 56

Only Rasmus looks basically average here, but he gets an additional twist — he just had one of the league’s best arm ratings, so he’s defensively capable in a different way. He’s shown maybe average range, with a dangerous throwing arm. Souza just took a huge step forward in plays made between 2015 and 2016. He looks, now, like a perfectly acceptable range-y type. And then there’s the top three. Smith has been rated before as possessing 80-grade speed, and he just fielded like it. Kiermaier catches everything that’s humanly possible to catch. And, you know those Statcast 5 Star plays? The plays that are most difficult to make? Bourjos just tied for fifth in most such plays converted, equaling Lorenzo Cain and Kevin Pillar. His overall plus/minus found him sandwiched between Keon Broxton and Jason Heyward.

We used to write about Bourjos plenty around here, when he was younger and it looked like he could become a thing. He hasn’t been able to hit, but the evidence makes it look like he’s still a defensive wizard. If the Rays ever were to run out an outfield of Bourjos — Kiermaier — Smith, all those square feet could become a baseball graveyard. I wouldn’t count on that alignment too often; Bourjos was just acquired as a reserve, and Smith could still need some more seasoning. But this shows you how deep it goes. Rasmus — Kiermaier — Souza is already a good trio, and then there’s still more. This isn’t some special organizational secret, some kind of new market inefficiency, because this has already been a market inefficiency. Yet, in the infield, the Rays have been willing to take some defensive chances. In the outfield, they’re betting on range, and on Colby Rasmus’ arm.

It’s all in the name of run prevention. We’ve been over the run-scored/run-allowed conversation a million times and we don’t need to make it a million and one. The Rays outfield might not be big on hitting, and that’s going to cost a game here and there. But no outfield in the majors looks better prepared to run almost everything down that it can. Peter Bourjos isn’t the reason for that, but you can consider him an indicator.