At 21.6 runs above average, Ervin Santana’s slider has been his best pitch on the season. Only Max Scherzer (30.0) and Jhoulys Chacin (22.4) derived more value out of the pitch on the year. It’s a stellar pitch and quite possibly his best weapon.
But here’s why it is going to used more tonight.
In his most recent start against the Yankees on September 1st, Ervin Santana threw 70.8% sliders against the Yankees right-handers. Over the entire year, the next highest slider usage vs righties was 58% against Cleveland in his last start of the year (perhaps honing his craft for the one-game playoff). Most of Santana’s games that rate fell around the 50% mark (50% fastballs/50% sliders). It is clear that with the Yankees in New York, Santana throttled down on the pitch.
This is big because if there is one pitch that the Yankees’ right-handed contingency has had trouble against it is sliders from right-handed pitchers. Perhaps no one more so than Aaron Judge. The Bronx superman has very few holes but sliders from righties gives him fits. He doesn't expand the strike zone much but he will swing through sliders on the outer-half. In the three plate appearances against each other this year, Santana threw 10 sliders on 14 total pitches. In their first match-up, Santana threw two straight fastballs, got a strike with a slider then, behind Judge 2-1 in the first inning, he tried to sneak a fastball past the hulking Yank to unfavorable results. Over their next two match-ups, Santana threw sliders nine of the next 10 pitches – striking him out once and inducing a long fly to Byron Buxton.
This just goes to show how little room for error there is with Judge.
Gary Sanchez, meanwhile, is a little more adept at getting to the slider -- he's hitting .283 vs sliders from righties. The biggest soft spot in his swing vs sliders is burying the pitch down and away outside of the strike zone. He will chase but Santana has to avoid throwing it in the strike zone, even down-and-away. Santana threw Sanchez sliders on 8 of the 12 pitches in their three match-ups this year.
Starlin Castro has shown the ability to make contact on sliders, particularly those thrown down-and-away, and find some seams on the ground. The good news is that they are mostly singles on the ground, so a shift with Polanco to his right and Dozier covering the middle of the infield could keep Castro from doing damage. The danger comes from hanging Castro a slider inside where he has shown he is very capable for turning and elevating those pitches.
Santana has allowed seven home runs on his slider to righties this year, the most since his final season in Los Angeles (where he posted a 5.16 ERA). Unlike that season in LA, Santana has learned to throw it away from contact, locating the slider in non-competitive locations (areas that hitters can't touch it) and getting less contact.
As you watch tonight, look for Ervin Santana to use his slider liberally to the right-handed bats.