Digging Into the Data Behind Baseball’s 10 Toughest Pitches

The fastball of Cy Young. The curveball of Sandy Koufax. Steve Carlton’s slider, Pedro Martinez’s changeup and Mariano Rivera’s cutter. The out pitch has been alive as long as the game of baseball itself. When a pitcher needs a strike – or especially a strikeout – there’s nothing more comforting than having a weapon in his arsenal that’s almost guaranteed to induce poor contact or none at all.

There’s perhaps no more signature pitch in the majors today than Clayton Kershaw’s curve, and the reigning NL MVP’s dirtiest delivery is among the top 10 of the toughest for hitters to turn into a hit this season. To qualify for our list, the parameters are pretty simple – a pitch has to have been thrown at least 225 times and account for at least 15 percent of the total thrown by a pitcher. (Why 225? We’re operating as a baseline of 350 for a season, the season is roughly 64 percent over, and 64 percent of 350 is just about 225). We’re sorting by the lowest batting average that pitches which fall in those categories produce, so you’ll notice a lack of fastballs.

But let’s start with an honorable mention for a guy who only throws two pitches – both of which happen to be among the best in baseball. (All GIFs are copyright MLB Advanced Media)

Dellin Betances (NYY)
The pitches:
Curveball, fastball
Pitches thrown: 444, 425
Average velocity: 83.4, 96.7
Usage percentage: 51.1, 48.9
Average against: .111, .129

Arguably the nastiest reliever in baseball doesn’t need more than two pitches to send hitters back to the dugout wondering what the heck just happened. After leading all relievers in Fangraphs’ WAR (3.1) last season, Betances has posted virtually the same stats across the board in 2015 – the ERA is slightly better, the FIP slightly worse, a few more strikeouts and a few more walks.

But it’s been even tougher for batters to make contact after hitting .149 off him in 2014, and the most impressive part of his .120 opponents’ average this season is that he’s been almost equally dominant with both pitches. The curve remains his putaway – 59 of his 87 strikeouts have come on the hook – but the fastball is still good enough to induce swings and misses 32.0 percent of the time, fifth best in the majors. And keep this in mind for later: Neither of Betances’ weapons even qualifies as the best in the Yankees’ bullpen.

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10. Charlie Morton (PIT)
The pitch:
Pitches thrown: 257
Average velocity: 78.6
Usage percentage: 21.8
Average against: .109

Perhaps the most surprising name on this list checks in first largely thanks to horizontal movement. The sweeping motion of Morton’s curve produces the third-largest dip in baseball behind Dallas Keuchel’s (more on him in a bit) and Corey Kluber’s, breaking an average of 9.8 inches horizontally.

That explains why it’s so tough against right-handers. Righties have a total of three hits this season off a Morton curve that’s designed to break low and away from their reach. On the few times it doesn’t, you get a chance to do what Yunel Escobar did.

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Morton’s success is designed around a sinking fastball that produces a ground-ball rate that’s among baseball’s best when it’s actually sinking, but it’s also easily his most hittable pitch. Sixty-seven of the 75 hits he’s allowed have come on either his two-seam sinker or his rarely seen four-seam fastball. Batters are hitting .071 against a changeup Morton throws his 7.6 percent of the time, and when that curveball is diving away from righties – like this pitch to Miguel Sano did – the Pirates have a pretty solid fourth starter on their hands.

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9. Sonny Gray (OAK)
The pitch:
Pitches thrown: 387
Average velocity: 86.2
Usage percentage: 17.5
Average against: .109

Gray’s slider usage has spiked over the past few years, and it’s now surpassed his curveball – which is also very, very good – as his go-to breaking pitch. Batters whiffed on Gray’s slider 34.4 percent of the time in 2014, but that’s been kicked up to a 42.4 percent rate this season that ranks 12th in the majors among starters.

With one of the AL’s worst records, the A’s are a playoff afterthought, but they’re dynamic to watch every fifth day because of Gray. He’s as good a bet as any to win the AL Cy Young at this point, and he’s completed eight innings in six of his 22 outings while allowing a .175 average past the sixth – making Gray the only starter to hold opponents below .200 from the seventh on. A lot of that is because of the increased effectiveness of his slider.

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8. Joaquin Benoit (SD)
The pitch:
Pitches thrown: 244
Average velocity: 83.9
Usage percentage: 34.6
Average against: .108

Of all the Padres rumored to be winding up with new addresses prior to last week’s trade deadline, Benoit was perhaps the most puzzling name to keep his San Diego uniform. Not because he isn’t good – quite the opposite – but because he’s been so effective as a setup man getting to Craig Kimbrel and can become a free agent at season’s end.

He’s making $8M this season and has a team option for the same price tag in 2016, and there are some warning signs about his performance aside from the fact that he just turned 38. Most alarmingly, his .147 batting average on balls in play is on pace to be the best of … well, all time for a pitcher to throw at least 40 innings.

Joaquin Benoit 2015 SD .147
Juan Moreno 2001 TEX .157
Matt Cain 2005 SF .159
Vicente Romo 1968 CLE .169
Troy Pervical 2008 TB .169
Will Harris 2015 HOU .171
Carlos Marmol 2008 CHC .171
Tyler Clippard 2013 WAS .172
Junior Thompson 1946 NYG .175
Caleb Thielbar 2013 MIN .175


So, that’s probably something that might not sustain for two more months. One thing that could is his splitter, which produced an absurd .071 opponents’ average in 2014 before its current higher-but-still outstanding rate. Make no mistake, this is a pitch designed for hitters to chase. It’s catching the zone just 26.6 percent of the time, the third lowest of any pitch that qualifies for our list. Jorge Soler found that out the hard way.

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7. Jimmy Nelson (MIL)
The pitch:
Pitches thrown: 358
Average velocity: 86.9
Usage percentage: 18.2
Average against: .104

Nelson was pretty strictly a fastball/slider pitcher as a rookie with the Brewers in 2014, but introducing a curveball has actually turned his slider into his most effective pitch. And he needed it, because his fastball is almost as hittable as they come, ranking 83rd (8.8 runs below average, per Fangraphs) of 92 qualified pitchers.

His curveball is essentially average, but it’s keeping hitters off balance enough at 82.3 mph that it’s setting up a slider that’s made him a beast against right-handers (.204 average, .580 opponents’ OPS), and is registering at 11.3 runs above average. Batters are swinging and missing at Nelson’s pitches 23.9 percent of the time – up from 21.3 last season – and if he can continue to refine his curve or add some movement to his fastball, the Brewers may have something. The effectiveness of that slider, at the very least, doesn’t appear to be diminishing anytime soon.

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6. Francisco Liriano (PIT)
The pitch:
Pitches thrown: 667
Average velocity: 84.8
Usage percentage: 34.2
Average against: .098

A lack of control has been Liriano’s bugaboo throughout a career of enviable highs and disastrous lows, but he’s harnessed his wildness in 2015. His 2.99 walks per nine innings are his fewest since 2010 and his 1.06 WHIP is his lowest since his 2006 rookie season in Minnesota. The lefty’s constant has been his ability to induce swings that miss, and his 33.8 percent rate leads the league for the second straight season.

So what are hitters swinging at as they keep the air properly circulated around PNC Park? A slider with a whiff percentage of 45.8, second among starters behind San Francisco’s Chris Heston. And check out where they’re going from a catcher’s perspective. There’s a reason lefties are slugging .267 against Liriano since he got to Pittsburgh – the lowest off any pitcher to face at least 250 southpaws since 2013 other than Chris Sale.



Fangraphs has Liriano’s go-to weapon at 20.0 runs above average, making it the second-most valuable pitch in baseball behind Max Scherzer’s fastball (20.6). Not convinced? Ask Bryce Harper.

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5. Clayton Kershaw (LAD)
The pitch:
Pitches thrown: 389
Average velocity: 73.5
Usage percentage: 18.0
Average against: .094

Iconic in its effectiveness and in its 12-to-6, bottom-dropping-out movement, Kershaw’s curve is the fifth slowest of the 68 pitchers to hurl at least 200 toward the plate. It’s an out pitch he mixes in with his more prominent fastball and slider, and the drop-off in velocity is stark. Kershaw’s slider runs in at an average of 87.5 mph, the 10th fastest of its kind, but the curve is 14 mph slower. Batters are swinging and missing at Kershaw’s Uncle Charlie 42.2 percent of the time – nearly a six percent improvement over 2014. He has a major league-leading 68 strikeouts on curveballs, accounting for more than 35 percent of his overall Ks for something he uses a little more than once every six pitches. And even when they do make contact, more than nine out of those 10 turn into outs. Kershaw likely isn’t going to win another Cy Young in 2015 and won’t repeat as MVP, but his signature pitch is the best it’s ever been. Let’s again pick on the likely frontrunner to follow Kershaw as NL MVP to show just how good it can be.

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4. Dallas Keuchel (HOU)
The pitch:
Pitches thrown: 405
Average velocity: 79.6
Usage percentage: 17.6
Average against: .092

If the under-the-radar Nelson wants a realistic career path to follow, he might not need to look any further than the next member of our list. Keuchel was a relatively unheralded prospect in a strong Astros system prior to arriving practically out of necessity in 2012, and the 5.04 ERA he produced over his first 38 major league starts that season and the next gave little indication he would one day be starting an All-Star game.

But thanks to the development of his slider, that’s exactly what he did in mid-July. Keuchel isn’t getting anywhere based solely on his fastball, which scoots in at an average of 89.6 mph. Although he’s learned to locate far better with his rather modest heater, a changeup (78.7 mph) that’s virtually indistinguishable speed-wise with his slider has made the movement of the latter nearly impossible for lefties to track. Southpaws have a .374 OPS against Keuchel, which by season’s end would put him third all-time behind Chris Sale in 2013 (.360) and Mariano Rivera in 1999 (.365) among pitchers to face at least 150 left-handers. In 2013, Keuchel allowed hard-hit contact 30.5 percent of the time – roughly league average for a starter. Last season, that dipped to a major league-low 19.7 percent, and the lefty is on track to do it again (19.9 percent) in 2015.

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3. Pedro Strop (CHC)
The pitch:
Pitches thrown: 348
Average velocity: 82.7
Usage percentage: 49.9
Average against: .089

Strop is a classic two-pitch reliever, and it’s hard to make contact regardless of whether he’s throwing the fastball or his devastating slider. Opponents are hitting just .146 against Strop – third best among anyone to throw at least 40 innings – and his 37.5 percent swing-and-miss rate is only behind Aroldis Chapman’s, Betances’ and Kimbrel’s. His 55.7 percent whiff rate on sliders trails only Andrew Miller’s 56.3, and an astounding 43 of his 52 strikeouts have come when throwing the hook.

Strop’s slider is the best out of any bullpen in baseball per Fangraphs, registering at 8.9 runs above average. He’s allowed 23 hits in 47 innings but has walked 21 and hit four batters, so his problem isn’t contact – it’s having a hitter keep the bat on his shoulders. When Strop can get ahead in the count and get someone to chase, there are few pitches better than his slider.

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2. Andrew Miller (NYY)
The pitch:
Pitches thrown: 297
Average velocity: 84.0
Usage percentage: 51.6
Average against: .069

Miller would have topped this list last season, holding opponents to a .071 average against his slider during stints with Boston and Baltimore, but his best pitch has been even nastier in the third stop of his AL East tour. The Yankees gave the left-hander a four-year, $36 million deal to be the long-term fix for the fireman role Mariano Rivera finally gave up in 2013, and so far the results have been fantastic.

Right-handers have a .341 OPS against him, the second-lowest mark by any lefty against the opposite side of the plate since 1974. He has thrown nearly 300 sliders and surrendered five hits, none of which went for extra bases until Chris Davis’ solo homer July 22. Miller’s drop-off-the-table slider has been the single most difficult pitch to hit in the majors over the past two seasons.

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1. Francisco Rodriguez (MIL)
The pitch:
Pitches thrown: 242
Average velocity: 82.7
Usage percentage: 43.1
Average against: .063

Rodriguez’s changeup has always been his best pitch dating back to the days when he was piling up saves in Anaheim, but it’s been another level of effective in 2015. If the five hits in 79 official at-bats that ended with a Rodriguez change weren’t enough evidence, there’s this Fangraphs list of the most valuable changeups from relievers since 2002.

Fernando Rodney 2012 TB 20.6
Guillermo Mota 2003 LAD 18.3
Eric Gagne 2003 LAD 15.9
Hideki Okajima 2007 BOS 15.9
Ryan Madson 2011 PHI 15.2
Francisco Rodriguez 2015 MIL 14.9
Ryan Madson 2004 PHI 12.9
Eric Gagne 2002 LAD 12.7


We’re just a few days into August, so there’s nearly two months for Rodriguez to add to a changeup that’s barely behind Zack Greinke’s (17.3) in terms of runs above average – and the NL Cy Young favorite has more than 100 additional innings on Rodriguez. He just made his sixth All-Star game appearance, but he’s a completely different pitcher than the one that had a power fastball and a wicked slider with the Angels in the mid-2000s. Rodriguez is almost exclusively fastball-slider at this point in his career, and the fastball – which hitters are drilling to the tune of a .389 average – isn’t fooling anyone. But if he gets two strikes on a hitter, it’s typically game over. Batters are 9 for 82 (.110) with no more margin for error against Rodriguez, when the changeup is almost always coming – like Jeff Francoeur found out.

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Brett Huston is a senior editor at STATS LLC. Contact him at bhuston@stats.com or on Twitter @BHuston_STATS.

AP Photo/Mark J. Terrill