The 2020 season came and went in a flash, but plenty of rookies still took the opportunity to leave their mark. As the new year begins, we're looking back at the ones who left the biggest impressions.

We already covered the star rookie hitters. Now it's time to take a look at the rookie pitchers -- using Statcast's tracking technology to pick out the ones who showed signs of even bigger things to come, by showcasing skills beyond the traditional "baseball card" stats.

Here are nine rookie pitchers who stood out in 2020.

Devin Williams, RHP, Brewers
Key stat: .032 AVG allowed on changeup

We have to start with the National League Rookie of the Year and Reliever of the Year. Williams burst onto the scene as the most dominant reliever in baseball, period -- he had an 0.33 ERA and struck out over half the batters he faced -- thanks to a magical "airbender" changeup that was baseball's best pitch, period.

Here are just some of the fun facts about Williams' airbender:
• Hitters went just 2-for-62 against it … with 41 strikeouts. Williams' .032 batting average allowed on changeups was the lowest on any single pitch in baseball in 2020, out of the 418 pitchers with 50-plus plate appearances ending on one pitch type.
• Williams' changeup drops 8.3 inches more than an average MLB changeup and breaks horizontally 4.7 inches more than an average changeup. His vertical movement was fourth-best in MLB, and his horizontal movement was second-best.
• Williams has a uniquely high changeup spin rate. A changeup is typically a low-spin pitch, but because Williams releases his like a screwball, he averages 2,852 rpm. That's over 400 rpm higher than any other changeup. It's over 1,000 rpm higher than the MLB average changeup spin rate, 1,767 rpm. Williams' changeup spin would be high if it were a curveball, forget about a changeup.

Sixto Sánchez, RHP, Marlins
Key stat: 17.3" 2-seamer movement/17.1" changeup movement

The Marlins' star prospect lived up to the hype in his 2020 debut, and he looks like the next great ace in Miami. The 22-year-old Sánchez used an electric fastball-changeup combo to help lead the Marlins on their surprise playoff run. Sixto's triple-digit heat is overpowering by itself -- he had four strikeouts on 100-plus mph fastballs, already the most by any Marlins starting pitcher in the pitch tracking era, which goes back to 2008. But it's even more devastating in tandem with his changeup, which is probably an even nastier pitch.

This might be the coolest part: Sánchez's two-seam fastball comes in at 97 mph, and his changeup comes in at 89 mph, but they have nearly identical movement. The two-seamer breaks 17.3 inches horizontally, and the changeup breaks 17.1 inches horizontally … both of which rank near the top of the league. So good luck differentiating them, let alone hitting them.

Ian Anderson, RHP, Braves
Key stat: 2.57 expected ERA

The Braves' top pitching prospect was called up and pitched like an ace for the NL East champs down the stretch, with a 1.95 ERA in the regular season and 0.96 ERA in the postseason. Anderson excelled by suppressing hitters' quality of contact. Of the 81 batted balls against him, only a single one was barreled -- that means hit with ideal exit velocity and launch angle -- giving him MLB's lowest barrel rate at 1.2% (of the 200 pitchers with 75 or more batted balls against them). Barrels generally go for home runs or extra bases, and Anderson essentially never allowed them. That's why his Statcast expected ERA -- based on quality of contact allowed, strikeouts and walks -- was just 2.57, the second-best xERA among starting pitchers who faced at least 100 batters in 2020, behind only NL Cy Young Award winner Trevor Bauer.

Dustin May, RHP, Dodgers
Key stat: 2-seamer with 97.9 mph velo/18.8" of break

We knew what kind of stuff May had after his brief debut in 2019, but it was fun to get to watch it all year in 2020 as May jumped from not even being on the Dodgers' roster to lights-out, last-second Opening Day starter to key member of the World Series champs' pitching staff. For May, it all starts with a nasty two-seam fastball that has an elite combination of velocity and movement. May's two-seamer averages 97.9 mph, fourth-fastest in the Majors (plus, he dials it up over 100 mph routinely); it also gets 18.8 inches of horizontal break, third-most in the Majors. May is the only pitcher who got that kind of running action at that high velocity. Just ask Manny Machado how hard it can be to hit.

Garrett Crochet, LHP, White Sox
Key stat: 62.5% of fastballs thrown 100+ mph

Crochet went from being drafted 11th overall in June to blowing hitters away in the big leagues by September. The 6-foot-6 lefty has the big fastball to match -- Crochet hit triple digits on the radar gun on 45 of the 72 fastballs he threw, 62.5%. Nearly two in every three fastballs you throw being over 100 mph is insane. The next-closest pitcher, Brusdar Graterol, only threw 26.2% of his fastballs 100-plus mph. Only three other pitchers have hit the 100 mph mark at such a high clip in a season since pitch tracking began -- Aroldis Chapman, Jordan Hicks and Mauricio Cabrera. Crochet notched strikeouts this year at 101.5 mph, 100.8 mph, 100.5 mph, 100.2 mph and 100.1 mph. Serious fire.

Jesús Luzardo, LHP, A's
Key stat: 95.4 mph avg. fastball velo

The 23-year-old Luzardo hasn't fully put it all together ... yet ... but when he does, look out. The much-hyped overpowering stuff is real. Luzardo stands out first and foremost because of his dominating velocity from the left side -- his average fastball velocity in 2020 (four-seamer and sinker combined) was 95.4 mph, the highest among regular left-handed starters, ahead of Blake Snell. And he routinely dials it up into the upper 90s, with 12 of his strikeout pitches last season clocking in at 97 mph or faster. Couple those fastballs with two wipeout secondary pitches -- Luzardo's changeup and curveball both made hitters whiff on 45% of their swings in 2020 -- and you get all the makings of a future ace in Oakland.

James Karinchak, RHP, Indians
Key stat: +3.6 inches of fastball rise vs. avg.

If not for Williams, Karinchak would have been the breakout rookie reliever of 2020. The Indians righty was dominant in his own right, with a 48.6% strikeout rate that was second only to Williams and a 17.67 K/9 mark that actually tied Williams for the best in MLB. Karinchak's funky delivery and extreme over-the-top release point make him extremely tough to hit, and extremely fun to watch pitch.

Karinchak's rising fastball and straight vertical curveball work perfectly together. His four-seamer comes in at 95.5 mph and gets 3.6 inches of "rise" above average, the second-best rising fastball movement in the Majors behind Bauer. And because his curveball only moves 2.4 inches horizontally, it looks exactly like his fastball until the bottom falls out -- it drops an average of 46.6 inches.

Casey Mize, RHP, Tigers
Key stat: +5.3 inches of splitter drop vs. avg.

Mize had his share of growing pains in his debut season, but the Tigers' 23-year-old top pitching prospect also flashed the talent that made him the No. 1 overall Draft pick in 2018. The pitch everyone wanted to see was Mize's splitter, which drew 70-grade scouting reports, and the Statcast data that came in once he started throwing it on the big league stage didn't disappoint. Mize's splitter got the second-most vertical movement of any MLB splitter, dropping 5.3 inches more than average. But maybe the best part? It looks so much like Max Scherzer's wipeout changeup, a welcome callback for Tigers fans to Scherzer's dominant days in Detroit.

Josh Staumont, RHP, Royals
Key stat: 102.2 mph max velo

Who would've guessed what the Royals would have in Staumont? The 27-year-old showed impressive velocity in a cup of coffee in 2019, but it was nothing like what he brought in 2020. All of a sudden, his fastball turned into the biggest fastball in the Majors. Staumont didn't touch 100 mph once in 2019; in 2020, he hit triple digits 36 times, including 101 mph 20 times and 102 mph twice. Staumont threw the fastest overall pitch in MLB in 2020 -- 102.2 mph, tied with one by Jacob deGrom. He also had the fastest strikeout pitch -- 102.0 mph -- and four of the top five. Staumont notched more 100-plus mph strikeouts (eight) and 101-plus mph strikeouts (five) than any other pitcher, on top of being the only one with a 102 mph K.