Last week's edition of Raising Aces examined the stuff and mechanics of CC Sabathia and Josh Johnson—a couple of typically great pitchers who have fallen on hard times—in an effort to explain their struggles. This week we flip the script, studying a pair of pitchers who have greatly exceeded expectations in 2013 to find out whether each pitcher's success is sustainable. Under the microscope today: Francisco Liriano and Justin Masterson, both of whom could conceivably headline playoff rotations this fall.

Francisco Liriano
Liriano has been an enigma throughout his career. As a 22-year-old, the left-hander garnered comps to Minnesota teammate Johan Santana, recording 177 strikeouts against just 39 walks over his first 145 innings in the big leagues. The balloon burst when he underwent Tommy John Surgery following the 2006 season, after which he wasn’t the same. But Liriano has rediscovered his mojo this year, and through 100 frames he is invoking memories of the '06 breakout that originally put him on the national radar.







2005 – 2012














The numbers are even more staggering when we remove Liriano’s successful seasons from before the surgery and focus just on the stats that he had compiled in the time between his elbow scar and the start of the 2013 season. From 2008 through 2012, Liriano posted a 4.75 ERA with a 1.42 WHIP, and his 22.1 percent strikeout rate was undermined by a 10.5 percent walk rate. His ERA topped 5.00 in each of the past two seasons (and three of the past four), and he surrendered five walks per nine frames over 291 innings pitched from 2011 to 2012.

Walks have always been the biggest thorn in Liriano's side, and though his 10 percent rate this season represents one of the better marks of his career, it’s still well worse than league average, and his near-2.00 ERA will not likely persist in the face of so many free baserunners. Liriano has thrived by keeping the ball in the yard at a career-best rate while allowing only 6.7 hits per nine innings, a mark that’s been helped by a Pirates unit that ranks first in the National League in Defensive Efficiency.

The left-hander generates a bundle of groundballs at his best, and this season's 55 percent grounder rate is a near match for his career-high frequency of 57 percent, achieved in his breakthrough performance of 2006. Liriano has cracked the 50 percent mark for groundballs in only one other year in the majors, posting a 56 percent rate in 2010, which until 2013 stood out as his most productive post-surgery campaign.

There is a strong connection between Liriano's groundball rates and his run prevention. The underlying ingredients include the excellence of the Pittsburgh defense, the impossibility of hitting groundballs out of the park, and the southpaw's ability to keep the ball down. Liriano has been able to consistently bury his pitches under the zone this season, as indicated by a heat map that cools as it rises.

Because he’s inducing more chases than ever, Liriano is generating more strikes this season despite throwing more pitches out of the strike zone. Compare the above chart, in which only red squares show up below the shelf of the strike zone, to Liriano's colorful heat map from the 2011 season:

His strikeouts are still below the 30 percent rates of his pre-surgery days, but he is fanning more batters than in any season since going under the knife. The weapon behind Liriano's success, both now and in his capricious youth, is a knockout slider that secures flailing swings against some of the best bats in the world.

The slider is Liriano's weapon of choice, and he has gone to the pitch more than 37 percent of the time this season. Opposing batters are hitting just .119 versus the slider this year, with a .222 BABIP and only five extra-base hits allowed, and Liriano has struck out 77 batters in the 151 at-bats that have ended on the pitch. His slider has always been able to mute opposing batting averages, but this season's batted-ball numbers are easily the best that he has seen in the years for which we have data available (since 2007).

While the heater has not been quite as dominant as the breaking ball, Liriano's fastball improvement this year might be even more responsible for his leap forward. Consider that from 2011-'12, Liriano gave up .307 batting average with a .476 slugging percentage vs. his heat (combined four-seam and sinker, stats via Brooks Baseball). This season, batters are hitting .279 with just a .368 slug, and Liriano has greatly reduced his walk rate on fastballs.

The velocity has remained virtually unchanged since last year, but fastball command is the most valuable tool that a pitcher can possess. It’s the key to getting ahead in the count, which allows Liriano to uncork his wicked slider in favorable situations. The fastball also sets up the deception of the slider when he can keep the ball down, allowing one pitch to mask the other, and this season Liriano has consistently been able to find the shoe-tops of right-handed batters on the breaking pitch while also burying it under the zone versus lefties. Finally, Liriano's changeup has occasionally flashed video-game movement, with ridiculous arm-side run that streaks away from right-handed hitters.

Liriano is still a bit of a mechanical mess, with instability and spine-tilt littering his delivery near release point. The lefty has an open stride that finishes with an inconsistent landing, and he’s prone to elbow drag when he misfires the rotational elements of his delivery. His timing is volatile, but improved balance early in the delivery has allowed him to find a more consistent release point this season. However, his release point also varies based on the identity of the batter.

Liriano starts on the first-base side of the rubber when facing left-handed batters in order to exaggerate the incoming trajectory of his pitches, but he shifts to the extreme third-base side when facing opposite-side bats. While this strategy can provide a functional advantage, it also adds a complicating factor to an already shaky delivery, and I would discourage all but the most efficient pitchers from adding such a tweak to their mechanics. The strategy is nothing new to Liriano, who has been shifting his setup for years, and his newfound success provides little incentive to make an adjustment.

Justin Masterson
Masterson has shown extreme platoon splits for years, thanks to a low arm slot that can give right-handers fits yet plays right into the hands of lefties. Same-side batters have a sub-.600 OPS versus Masterson in his career, but left-handers enjoy an OPS almost 200 points higher. In response, opposing managers have stacked their lineups to give Masterson the platoon disadvantage 56 percent of the time.







2008 – 2012














Lefties are still reaping the OPS platoon advantage to the tune of 200 points, but the OPS baselines have dropped nearly 100 points on each side of the plate. Two of Masterson's three true outcomes fall right in line with his career numbers, but his K rate is seven percentage points higher than the stable frequency he’d posted in each of the previous three seasons.

The Indians are in the middle of the pack in terms of defensive efficiency, yet Masterson has enjoyed a Liriano-like hit rate of 7.1 safeties per nine innings. Fewer baseballs are being put in play against Masterson, and fewer of those that reach the defense are falling in for a hit—his .282 BABIP is the lowest since his rookie season. He has also avoided giving up extra-base hits, with an opponents' ISO under .100 and just 18 doubles allowed in 24 starts this season.

The combination of missed bats and weaker contact suggests that Masterson is bringing superior stuff to the table this season. He is credited as a three-pitch pitcher, but two of those offerings are a fastball and sinker that often blend with respect to movement and velocity and are separated by just 2.5 mph on average. Consider the following set of pitches, the first labeled a four-seam fastball and the second tagged as a sinker:


The numbers say that the four-seamer has long been Masterson's most hittable pitch, and 2013 is no different, with opponents batting .297 with a .448 slugging percentage. He has thrown the sinker more often, coming in at 42 percent frequency compared to the 30 percent of the straight fastball, and with better results. Masterson uses a somewhat backwards approach, as he leans on the sinker more heavily to same-side batters, against whom he’s thrown it on half of his pitches.

Fastballs of various types make up 72 percent of Masterson's pitches this year, but his performance on heaters is very similar to 2012, a year in which he had a 4.93 ERA and 1.45 WHIP. As is the case with Liriano, the slider is the key to Masterson's statistical gains this season. The strikeouts tell the whole story: batters have struck out 99 times in 174 at-bats that ended with a slider, a ridiculous rate of 56.9 percent (compared to his 44.9 percent rate last season). Meanwhile, his fastballs have resulted in just 72 strikeouts in 430 pitch-ending at-bats (16.7 percent).

Masterson throws the slider to batters on both sides of the plate, but he favors the pitch to right-handed batters by a five-percent margin. The breaker has a more vertical trajectory than a typical slider, despite his sidearm delivery, and the downward movement aids the pitch's effectiveness against lefty bats. The slider has easily been Masterson's most dominant pitch from a performance standpoint, but what it has done to opposing righties in 2013 is downright criminal: in 85 at-bats that finished with the slider, right-handed batters have just two hits (both singles), for a .024 average and .000 ISO, in addition to 57 strikeouts. The pitch has just been filthy.

I mentioned the low arm slot in the intro, but the low-rider tale goes deeper than Masterson’s sidearm delivery. He has a very low center-of-gravity near the end of his motion, with heavy flex in his knees after foot strike, a physical detail that further shrinks his effective height at release point. Consider that Masterson stands six-foot-six yet releases the baseball from a vertical height of just five feet, three inches; in comparison, six-foot-five sidewinder Madison Bumgarner releases the ball from an area six inches higher.

Interestingly, Masterson's effective height at release point has been improving throughout his career. This season is an improvement over 2010-11, when his release height was right at the five-foot threshold, and his current position is nine inches higher than where it was in his rookie season. Often, exaggerated spine-tilt will artificially raise a pitcher's arm slot, but in Masterson's case, he can thank improvements in balance and functional strength for a solidified foundation to his delivery. The additional downhill plane allows him to reap the advantages of pitch trajectory (particularly on the slider), and at no cost to his release distance.

Thank you for reading

This is a free article. If you enjoyed it, consider subscribing to Baseball Prospectus. Subscriptions support ongoing public baseball research and analysis in an increasingly proprietary environment.

Subscribe now
You need to be logged in to comment. Login or Subscribe
Thanks Doug, fantastic stuff as always. Do you see Masterson's overall improvement as a long-term step forward, or more of a one-season outlier? Basiscally, is the increased K% here to stay?
Thanks, Tribe!

Pitchers can be different entities year-to-year, but I really like the overall trend of his rising release point as an indicator of his physical improvements.

The slider is Masterson's most effective pitch, and he has been using it more and more over the last few years, with a 3-yr frequency of 15.0% - 19.3% - 27.9%, so he is throwing it nearly twice as often now as in 2011.

The downward movement on all of his pitches is key, and the increased use of the slider as a wipeout pitch bodes well for his K rate moving forward. Time will tell if that all carries over into 2014, but I think that you can trust him for the rest of this season.
Thanks again. Really love your work.
Isn't there something about guys who increasingly rely on their sliders being linked to increased injury chances? I feel like I heard or read somewhere that a high percentage of sliders thrown is a warning sign
There is a potential connection there, though there are other factors to consider as well - whether they use pronation or a "twist," as well as the degree of pronation used. Liriano's frequency of 37% is definitely higher than you like to see, but I am not too concerned about Masterson's increased frequency as he is still under the 30% mark, and the vast majority of his offerings are still fastballs (72%, as compared to just 41% fastballs for Liriano).