Earlier this month, we introduced Catch Probability, our new Statcast™ defensive metric that attempts to answer a very complicated question in a relatively simple way. Given how far an outfielder has to go to catch a ball, and how much time he has to get there, how likely is it that the ball gets caught? That allows us not only to see how many total catches get made, but how difficult they were to make.
While the numbers will change slightly as we incorporate direction of travel and proximity to the wall in future releases, for now, simply going with distance and time has made for an extremely effective first step in judging catch difficulties, which allows us to do things like find Billy Hamilton's five most spectacular catches. We have also identified probability bands where we call certain plays "Five-Star Plays," which have a 0-25 percent likelihood of being caught, others "Four-Star Plays," which are 26-50 percent, and so on down the line.
You can see some preliminary leaderboards here. Feel free to check them out and have some fun, though know that they will change somewhat. (While Mark Trumbo is ill-suited in the outfield, for example, he won't look quite as poor as he does here once wall balls are accounted for.)
For our part, let's start with the simple question: Which outfields converted the highest percentage of tough plays? There's more than one way to answer this, of course. We could just go with the "highest percentage of Five-Star Plays," in which case we're looking at the Reds and Royals, or just "most Five-Star Plays made," which would be a tie between the Reds and Twins. But let's expand it a little more to "highest percentage of Four- and Five-Star Plays made," since that allows us to look at all batted balls with a Catch Probability of 50 percent and under -- that is, balls that turn into hits more often than not.
This isn't the same thing as "who had the best outfields," because not screwing up easy plays matters a lot, too. But in terms of making wonderful plays, these were the top five outfields.
 4. (tie) Twins, 23 percent
Minnesota cracks the top five here, and it's a great example that explains that "doing a great job of making highlight plays" is not the same thing as "doing a great job at overall defense." Thanks to Byron Buxton doing things like this…

... and Max Kepler doing things like this:

... the Twins did a fantastic job of making the toughest plays. However, neither Buxton nor Kepler played the entire season, and Minnesota's other outfielders like Robbie Grossman and Oswaldo Arcia managed to drag down the overall average -- the Twins, as a whole, converted the sixth-fewest number of catchable balls into outs. So while they pumped out highlight plays, they also didn't convert plenty of easier batted balls.
That was last year, though. It's very easy to see that changing in 2017 with a full year of Buxton in center, Kepler in right and Miguel Sano playing third base, not outfield.
 4. (tie) Rangers, 23 percent
For the most part, our Statcast™ defensive metrics have aligned reasonably well with the metrics we had before, with the names you expect to be at the top and bottom of rankings showing up exactly there. Texas may be our first interesting shift, because while Statcast™ has it as a top-five team both in getting tough plays and in getting to all balls, it was a mere 21st in DRS and ninth in UZR. That's a pretty big gap right there, so perhaps there's something specific about the Rangers that makes grading their outfield difficult, and we'll need to explore this one further.
Maybe it's just about reputation? After all, Jurickson Profar isn't really an outfielder, he's an infielder; he made a wonderful catch:

Carlos Beltran was 39 last year and best-suited to play designated hitter; he made a wonderful catch:

Shin-Soo Choo is probably going to be the team's main DH this year; he made a wonderful catch, too:

Ian Desmond was a shortstop and is now a first baseman; he made a wonderful catch, also:

It wasn't conventional, but this may have been a quietly good outfield in 2016.
 3. Royals, 27 percent
Kansas City has thrived on its famous outfield defense for years, riding it (along with an annually dominant bullpen) to back-to-back American League pennants and the 2015 World Series title, so you expect to see it here. Interestingly enough, however, Alex Gordon's best play was only the Royals' 20th-best play of the year. You're not surprised to see Lorenzo Cain doing great things:

But did you realize how often Paulo Orlando was doing great things?

Or Terrance Gore?

And, of course, Jarrod Dyson contributed as well, though he's since been dealt to the Mariners. The Royals always have a great outfield, and the data backs that up.
 2. Reds, 28 percent
As we noted above, this is largely about Hamilton being baseball's biggest highlight reel, so please do go enjoy our feature on how spectacular he's been. He caught 55 percent of the Four- and Five-Star opportunities he was given, the second best in baseball. But it wasn't only Hamilton, either. Adam Duvall and Scott Schebler each converted an above-average 27 percent of their tough opportunities, with Duvall standing out on this 14 percent Catch Probability dive:

Schebler got into the act, too:

 1. Rays, 30 percent
Immediately you're thinking, "This is because Kevin Kiermaier is great, right?" And you're absolutely correct to think so, as he's got a strong case for the best outfielder in baseball. When we noted above that Hamilton had the second-best rate of turning these tough plays into outs, it was only because Kiermaier was first, at 65 percent.

But as with Cincinnati, to rank this well, it's got to be about more than just one great center fielder. Here, for example, is Steven Souza Jr. making a Four-Star Play, his best of the year.

Let's not kid ourselves, though. This is about Kiermaier. This is why Tampa Bay is working to finish off that six-year contract extension. We're learning that no one can haul in outfield balls like he can.