Last season's best pitch could have a lot riding on it in ‘21.

With apologies to Devin Williams’ “Airbender” changeup, we’re referring to Dinelson Lamet’s high-octane, shape-shifting slider. It’s a pitch that Lamet rode (to a historic degree) to stardom last year, and it has everything to do with what he contributes to San Diego’s new super-rotation.

Lamet seemed untouchable at times. The Santiago, Dominican Republic, native racked up 10 strikeouts in four different starts, allowed six or fewer baserunners in all but two starts and finished with a 2.09 ERA, the lowest single-season mark by any starter in Padres history (with the short-season caveat). The only foe that bested Lamet was his own health; a murky arm injury, formally announced as a biceps ailment, shut him down just days before San Diego entered the postseason.

Lamet acknowledged this month that he would have likely needed a second Tommy John surgery had he tried to pitch through the pain. And as MLB.com’s AJ Cassavell has documented, no one will really know how much Lamet can pitch this year until he starts throwing his slider in game action. There’s a ton riding on the moment he does, and the reasons for that are threefold:

1. It’s possible that no starter has ever relied on a slider as much as Lamet did last year.

2. There’s a reason he used it so much; hitters can’t touch it.

3. At the same time, that slider puts the biggest strain on Lamet’s elbow.

Lamet broke through last year as a max effort, grip-it-and-rip-it force, dominating despite only throwing two primary pitches -- an upper-90s fastball and that slide piece.

That pedal-to-the-metal approach is likely how he’ll continue to thrive moving forward, but how long can he pull it off? Consider this: Lamet turned to his slider on roughly 53% of his pitches in 2020. Technically, he can make that slider look like two different pitches (a driving, horizontal cutter-style sweeper or an amped-up, power hammer), which is part of its charm.

But to answer the question that’s likely in your head -- yes, 53% is an absurd percentage. In fact, it’s the highest single-year usage rate tracked from any starter in the pitch-tracking era (since 2008), and it very likely could be the most any starter has ever relied on a slider.

Highest single-year slider usage rate, SP, since 2008
Min. 1,000 total pitches as a SP
1) Dinelson Lamet (2020): 53.4%
2) Chris Young (2016): 49.8%
3) Jhoulys Chacin (2019): 49.6%
4) Jaime Barria (2019): 47.0%
5-T) Jhoulys Chacin (2018): 44.8%
5-T) Tyson Ross (2018): 44.8%

You’d think hitters would start timing the pitch up after such repeated exposure, especially in last year’s regional-heavy format (Lamet faced the D-backs, Dodgers, Giants and Mariners in all but three of his starts). But that clearly was not the case. Roughly 40% of Lamet’s sliders ended in a called strike or a whiff. By MLB.com senior data architect Tom Tango’s run values formula, Lamet’s slider was baseball’s most valuable pitch (and it wasn’t close). Opposing hitters finished a feeble 10-for-125 (.080) with 71 strikeouts against the slider, putting it in contention for the most dominant pitch in recent times.

Lowest BA allowed on single pitch type, since 2008
Min. 100 PA ending on pitch type
1) Fernando Rodney (2012), changeup: .070
2-T) Dellin Betances (2014), knuckle curve: .075
2-T) Carlos Marmol (2008), slider: .075
4) Sergio Santos (2011), slider: .078
5) Dinelson Lamet (2020), slider: .080

That's four back-end relievers and Lamet in the top five. Across two starts against the Dodgers, Lamet held L.A.’s mighty lineup hitless with 12 strikeouts in 19 at-bats on sliders (including 11 punchouts in 16 at-bats -- and an absurd 48% whiff rate -- in a dominant Sept. 14 outing).

So yeah, there are plenty of reasons why Lamet would want to keep ripping that slider. But can his elbow handle that workload? Remember, we’ve never seen a starter lean that hard on a slider before. If Lamet goes with 50% sliders for a second straight year, that would be even more unprecedented.

The good news is that Lamet is already dusting off those sliders at camp, perhaps hinting he’s ahead of where many thought he’d be. He told reporters that he’s throwing without reservations so far.

“I'm trying to take the approach of always being prepared with all of my pitches,” he said, “so I'm trying to take the approach of always being prepared with all of my pitches, so that I feel as confident throwing the slider as I do the fastball as I do the changeup. It's to make sure I'm doing what I need to do and putting in the work in all the pitches, so I have all the confidence I need to throw each one of them.”

No one -- maybe ever -- was more confident in a slider than Lamet last year. He'll need to be confident in it again. The Padres' hopes don't necessarily hinge on Lamet; his injury concerns are why they went out and acquired Yu Darvish, Joe Musgrove and Blake Snell. But if the Friars want to unseat the mighty Dodgers, a healthy and fearless Lamet could put them over the top.