How Nestor Cortes Jr. stole a game for the Yankees

One point seven four eight. That’s the average number of runs given up when a team allows runners on the corners, with no out. There is an 86-percent chance a team will score at least one run in an inning where they manage runners on first and third, nobody out. It is one of the toughest spots for a pitcher to be in, and there’s not a single fan in baseball who doesn’t anticipate at least one run coming in.

Yesterday, Nestor Cortes Jr. didn’t care.

Domingo German did not pitch well in yesterday’s win over the Athletics. He had given up home runs in the first and third, and in the fifth, didn’t record an out. The Yankees were down 4-1 when Aaron Boone went to Cortes, knowing that 1.748 number, knowing that Cortes might just have to wear one for a team that has fallen behind a lot this season. Cortes is, nominally, farther down the bullpen depth chart than a guy like Chad Green or Zack Britton, and that’s the time when you bring in a guy farther down the bullpen depth chart.

Cortes struck out the first two batters he faced, and ended up working three shutout innings, bridging the game to those higher leverage arms, and putting up zeros until the Yankees could capitalize offensively. Sometimes momentum is easy to spot in a game, and although the Yankees didn’t take the lead for a couple more innings, Cortes’ work in the fifth, facing an 86-percent chance of giving up a run, completely turned the game around.

Here’s what his fifth inning looked like. There’s only one pitch that’s all that dangerous, everything else is away from the middle-middle part of the zone that gets pitchers in trouble — including German earlier in the game — and most striking of all is how much Cortes foregoes his slider.

Nestor does have four pitches he uses, but his fastball and slider make up about two-thirds of his repertoire. Yesterday, in the biggest leverage spot, he went away from the slider almost entirely, with his changeup and curveball picking up the slack.

This has to be a conscious decision, and the interesting question is why. Cortes’ slider isn’t very good, generating a lower whiff rate than the other three pitches, so the answer might be that this is a change the Yankees are trying to get him to make; fewer sliders, more curveballs, see if you can fool more hitters.

Except that in the sixth inning, with far lower leverage, Cortes’ slider usage was right back up around normal levels, before disappearing in higher leverage spots in the seventh, once a couple men had reached. In his best outing of the year, Cortes’ slider had an inverse relationship with leverage, despite being the pitch he uses more than any but his four-seam.

This leads me to believe a couple of things are possible. Immediately after coming in from the bullpen, the hitter has a couple of minutes to get a very brief scouting report, maybe getting to see a couple quick video clips while the reliever warms up, and then you have to go up and hit a guy you probably have never seen before.

Thus, ditching your second-most-common pitch can actually be really effective. I’ve never sat in an MLB on-deck circle, but I can imagine when a new pitcher comes in, especially in a high-leverage spot, your hitting coach pulls out a laptop, shows you his fastball, his slider, tells you those pitches are thrown 65 percent of the time, and that’s all you have time to gameplan for. Thus, by taking away a pitch like the slider, you upend a good chunk of the brief prep work a hitter was able to do.

The other explanation is specific to leverage, with less game theory needed. The Yankees might be perfectly ok letting Cortes use his slider in neutral and low leverage situations, but recognizing that when you need to make your pitch, his slider doesn’t fool enough hitters for it to be effective. So, onto a different pitch.

Whatever the justification, Nestor Cortes Jr. had a 14-percent chance of getting out of that inning clean. Being down 5-1 instead of 4-1 is a huge difference, especially for a team that has struggled to score over the course of the season. Dropping the slider was a huge part of the gameplan, and something to watch if Cortes is called upon in another spot like that.