What Was Marcell Ozuna Thinking?

With two outs in the bottom of the 10th inning on Monday, the Cardinals found themselves up by one run. Matt Bowman, the Cardinals pitcher, put himself in a little bit of trouble when Rhys Hoskins hit a single and then advanced to second on a groundout. Cardinals manager Mike Matheny put Bowman in considerably more trouble with the dubious decision to walk Carlos Santana and put the winning run on base in order to try for the double play. Bowman did not get the double play, instead striking out Jesmuel Valentin. That brings us to Aaron Altherr, the game’s final batter.

The win-expectancy chart provides a pretty good idea of what happened on that play.

Source: FanGraphs

If the graph doesn’t help enough, here’s a small clip of what transpired.

Marcell Ozuna dove for the ball and, by missing the catch, allowed Hoskins and Santana to score and win the game for the Phillies. Mike Matheny defended the aggressive play, because that’s what a manager is supposed to do. That doesn’t prevent us from asking the question, though: just how badly did Ozuna screw up by trying to dive for a catch he wouldn’t end up making?

A closer look at the play shows that the ball landed a bit short of Ozuna’s glove, and he would have needed an extra step to make the play.

To add injury to insult — or the reverse, depending on how you look at it — the ball caromed off Ozuna’s face and past him, which made the possibility of recovering even more distant for Santana. According to Statcast, Ozuna had almost no shot at the play.

Here's what disaster looks like if you're the Cardinals.

Marcell Ozuna aggressively goes for a ball with a 4% catch probability, and it gets by him for a walk-off two-run double. pic.twitter.com/Dwdda1WkB7

— Andrew Simon (@AndrewSimonMLB) June 19, 2018

That 4% figure is based on the average outfielder. Given that Ozuna possesses above-average speed, though, and is generally regarded as a good defender — combined with the fact that Ozuna got pretty close — the probability of Ozuna successfully making the grab were probably a little greater than 4%, though not too much greater. To assess Ozuna’s decision on the play, we have to account for the consequences of missing the catch plus three other variables: the chances of Ozuna making the catch, the chances of Ozuna getting in front of the ball were he to have taken a more conservative approach, and the chances of the ball getting by Ozuna like it did.

First, lets deal with the alternate universe where Ozuna makes the safer play and just tries to get in front of the ball. For the sake of argument and the example below, let’s say that there’s a 20% chance that the ball gets by Ozuna no matter what he does and that, in each of those cases, Santana scores the winning run. In that scenario, the Phillies’ win probability goes up to 100%. In this example, Ozuna gets in front of the ball 80% of the time with Santana stopping at third and Altherr at first. In that scenario, the Phillies’ win expectancy is 68.5%. That means, the safe play scenario looks like this:

We will use that as our baseline to judge Ozuna’s decision. We can now compare it to a scenario where Ozuna dives for the ball. Let’s say he has a 10% chance of catching the ball, and let’s say that, in the other 90% of the plays, the ball gets by him two-thirds of the time, while one-third of the time it hits his body or hat or face and bounces in front of him to prevent Santana from scoring. In this case, making the catch would be worth 74.8% WPA, as the Cardinals would then win. If he stops the ball, that is worth 6.3% WPA, as that is the difference between the baseline and runners on first and third. If the ball gets by him, that’s worth -25.2% WPA, because the Phillies just moved the baseline of 74.8% to 100%. Here’s what that calculation looks like.

Given the above parameters, the Ozuna decision is one that costs about 6% of WPA. By that estimate, he should have made the safe play. For comparison’s sake, let’s say the play was a bit of a fluke and that, in two-thirds of the plays where Ozuna misses the catch, the ball stays in front of him, while the ball gets past him and ends the game in only one-third of the diving plays. This is what that looks like.

If you believe this scenario to be true, then Ozuna did in fact make the right play. Whether you believe Ozuna played the ball correctly depends on your assessment of the variables involved. If you believe Ozuna had a 15% chance of making the catch, but there is only a 10% chance of losing on the safer choice and the odds of the ball bouncing away from Ozuna were 50/50 if he missed, then Ozuna made the right call at basically the break-even decision point.

The table below details a whole host of probabilities and the break-even number for the ball needing to stay in front of Ozuna for the play to be a good choice.

Keep in mind, some of these scenarios just aren’t plausible. If the ball is going to get by 30% of the time if Ozuna plays it safe, he can’t possible believe he is going to keep the ball in front of him 40% of the time if he dives for the catch. That middle scenario seems sort of reasonable, with a 20% chance that the ball gets by if he plays it safe, a 15% chance of a catch if he dives, and basically a 40/60 split of the ball getting past him if he misses.

Statcast’s 4% catch rate makes it look like a terrible decision, but Ozuna doesn’t know it is a 4% possibility when he breaks for the ball. He has to make the call on the fly. Keep in mind that Altherr’s ball traveled only 272 feet, but similarly hit balls by launch angle (between 17 degrees and 19 degrees) and exit velocity (between 94 mph and 95 mph) generally travel around 25 feet farther than the ball for which Ozuna dove. It’s reasonable to think Ozuna thought the ball might travel just a few feet farther with a tiny bit more hang time. That 4% catch rate is based on needing to travel 47 feet in 3.1 seconds. If Ozuna had needed to travel 45 feet and had 3.2 seconds, the catch rate jumps up into the 20s and makes diving for the play an easy call. Not making the catch ultimately cost the Cardinals the game, but based on the information Ozuna had at the time, it isn’t clear he made the wrong choice.