When the Texas Rangers selected high-schooler John Danks with the ninth pick in the 2003 amateur draft, they were under the impression that the 18-year-old southpaw would be the first of several homegrown hurlers to impact the big-league club. Danks moved swiftly through the system, reaching Triple-A Oklahoma during the 2006 season. While his minor league numbers were solid but less than exemplary, the Rangers decided that Danks could net a more major league-ready pitcher in trade, and they sent the 21-year-old to the White Sox along with Nick Masset in exchange for lanky right-hander Brandon McCarthy. The White Sox had most of their innings accounted for with Mark Buehrle, Jon Garland, Javier Vazquez, and Jose Contreras already in the fold, but they issued Danks a non-roster invitation to spring training, with an eye towards letting the newly acquired pitcher compete for the fifth spot in the rotation. Danks looked sharp in camp and, despite a six-walk performance to close out March, he made the team, debuting on April 8 with a six-inning, three-run six-strikeout performance against the division-rival Twins. He largely struggled for the remainder of the season.

Fast forward to the end of 2008, and suddenly this pitcher who’d had average minor league marks and a poor rookie season in the big leagues was the no-doubt-about-it, go-to guy in the 163rd-game playoff against those same Twins. How did such a dramatic transformation occur, and what enabled Danks to emerge as a legitimate ace?

Year  Age  Level  GP   IP    K/9 BB/9 HR/9
2006   21 AA/AAA  27  140.0  9.9  3.6  1.4
2007   22   MLB   26  139.0  7.1  3.2  1.8
2008   23   MLB   33  195.0  7.3  2.6  0.7

In 2006, Danks split time between Double-A Frisco and Triple-A Oklahoma and compiled an impressive strikeout rate. His translated minor league walk and home-run rates weren’t as sunny, but he definitely possessed tools worth harnessing. During the ’07 season in the major leagues, his strikeout and home-run rates hovered around their expected values given his minor league track record, but Danks actually exhibited improved control, posting a lower walk rate than he had against weaker competition. He was not the beneficiary of solid defensive play either, with a 5.02 DERA besting a 5.25 NRA by nearly a quarter-run per nine innings. Last season, Danks sustained the strikeout rate and vastly reduced his walk and home-run rates, both decreasing the number of runners that reached base and doing a better job of preventing runners from crossing home plate. The defense behind him was not drastically improved, but a 3.11 DERA/3.22 NRA is still excellent, especially for a 23-year-old.

Before taking the more circuitous, granular route in explaining the big turnaround in his performance, a macroscopic view of the situation can explain a great deal. Observe the pitch frequency data for Danks’ two major league seasons:

Year  Age   NP    FB%   CB%   CH%  CUT%
2007   22  2407  61.2  17.8  21.0  ----
2008   23  3144  52.2   6.4  19.9  22.5

Much like Esteban Loaiza in his breakout 2003 season as a member of the White Sox, Danks added a cutter to his repertoire. Loaiza’s new offering was primarily the byproduct of sessions with pitching coach Don Cooper, whereas Danks had apparently taught himself the pitch and perfected it with the help of both Cooper and rotation stalwart Mark Buehrle. That South Side triumvirate had worked on the pitch throughout the 2007 season, but they hadn’t considered it game-ready until spring training of ’08. The cutter moves away from lefties and in on the hands of righties, traveling a few miles per hour slower than his average fastball velocity. The development of Danks’ cutter is particularly interesting when you scroll through White Sox message boards, as one can see the pitch evolving from myth to inception to initial implementation during spring training, to the point that it really started dawning on observers that Danks had become a completely different pitcher.

Getting a bit more microscopic now, the cutter reduced the overall contact made against Danks, and the majority of those hitters who were able to get their bat on the ball did so rather feebly. Danks threw more pitches out of the zone last season, and he saw his out-of-zone swing rate increase from 18 percent to 27 percent. With the added swings, contact made on these out-of-zone pitches still decreased from 66 percent to 61 percent. Even more interesting, thanks to the late action of the cutter, Danks actually reduced his in-zone contact rate from 87 percent to 82 percent. The more feeble contact led to a complete reversal in his distribution of grounders and fly balls. In 2007, Danks allowed 46 percent fly balls which, when coupled with a 14 percent HR/FB rate, resulted in plenty of gopherballs. Last season, his fly-ball percentage plummeted to 34 percent while the HR/FB rate dropped to eight percent; fewer offerings were being lofted into the air, and even fewer were finding their way into the stands. The league average is somewhere in the middle, around 11 percent, suggesting that a slight regression may be in order, but if, as everything seems to indicate, the cutter is for real, Danks could easily sustain that reduced rate.

While it isn’t clear whether the success of the cutter resulted in the decreased usage of his curveball, or his struggles with the curveball led to an increased dependence on the cutter, Danks ended up using his curveball as nothing more than a “show-me” pitch. Since his struggles with the curve have been well-documented in his two big-league seasons, the latter scenario seems much more likely. Regardless, the huge difference in these two years can be attributed to the addition of this tremendous new pitch. With the curveball no longer being a featured weapon in his arsenal, here is the velocity and movement data for his three primary pitches:

Year  Age FBVelo  FBMove  CutVel  CutMove  ChVel   ChMove
2007   22  90.8  7.4/10.1  ----   -------   82.8  7.9/9.6
2008   23  91.1  6.2/10.7  87.3   0.4/5.4   82.7  7.5/9.9

Danks threw his fastball slightly harder, but with opposite-trending movement components, increasing the rise at the expense of the tail. This might not be a significant shift for other pitchers, but the addition of the cutter was allowing Danks to throw two different types of fastballs, and the tail on his changeup, coupled with the eight-to-nine mph drop in velocity was easily fooling hitters. Velocity and movement data often make more sense when presented visually, and below are diagrams of the above data in action, charting the relationship of velocity to both horizontal and vertical movement.


Danks did an excellent job of staying away from hitters with the fastball, which in turn extended the zone for the cutter, helping him to effectively shut down both sides of the plate. His fastball and cutter worked in tandem to increase one another’s effectiveness. For instance, a fastball on the outside corner to a lefty helps the hitter develop eye recognition between the pitch and location; however, the cutter can move a little more at the end, deceiving the formerly confident batsman. If he anticipates the cutter outside but sees a straighter fastball, his swing may go long, resulting in feeble contact at best. As a result, Danks looks like a reverse lefty, limiting right-handed hitters to a measly .240/.295/.375 line while holding lefties to an only marginally better .264/.324/.358. Danks’ rate of swinging strikes increased as well, which makes sense given the slight rise in his K/9-reverting to last week’s study, he was classified as a neutral pitcher in both seasons. The addition of the cutter improved his controllable rates, but not to the point that he became a power pitcher.

His classification did inch closer to that of a true power pitcher though, and with another subtle increase in strikeouts, this could very well be attained in full here in 2009, a fascinating development given that the horizontal movement on his fastball more closely resembles the finesse pitcher’s average, while the vertical movement on the same pitch exceeds the average for power pitchers. It’s a best-of-both-worlds situation for Danks, and goes a long way toward explaining his success. The movement on Danks’ cutter can be meaningless on its own, but we can gain some perspective by comparing it to others. (Note that the new out pitch is in no way similar to Mariano Rivera‘s cutter, which is incomparable.)

Pitcher   Hor.  Vert.
Danks     0.44  5.36
Papelbon  0.53  5.33
Halladay  0.42  5.18

There are striking similarities in both areas and only minor differences. Jonathan Papelbon‘s 87 mph cutter, and Roy Halladay‘s 89-90 mph offering both have sterling reputations-though Papelbon calls his a “slutter” due to the pitch having slider-like tendencies. John Danks didn’t add just any run-of-the-mill cutter, but rather one that already ranks among the best in the game. The question that arises most often is some variation on whether or not the success experienced in 2008 might be classified as “fluky”-understandable given the small sample size and how often pitchers produce award-worthy campaigns only to fall off of the charts the next year (I’m looking at you, Dontrelle Willis)-but the Danks turnaround is the byproduct of a change in approach, not in luck-based indicators such as BABIP or left-on-base percentage. On top of that, Danks pitched consistently well, putting up a Flake mark of 0.23 that placed him in the top third of those with at least 180 innings last season. Despite a large jump from 139 innings to 195 innings, he ranked just 126th in Pitcher Abuse Points, suggesting that he pitched quite efficiently and was properly managed.

PECOTA’s weighted-mean projection sees Danks amassing 169 innings over 28 starts, with a 2.7 BB/9, 6.6 K/9, and posting a 4.03 EqERA. All told, this would give Danks a very solid 4.1 WARP. The innings may be a bit low for a guy considered the ace of his team, but the production looks solid nonetheless, and there simply is not much data from which to draw conclusions. Danks could just as easily rack up 200-plus innings with a 3.50 EqERA and come closer to his higher percentile PECOTA, or mastermind a repeat performance from this past season. The current projection places him right alongside the likes of Aaron Harang and Brett Myers. Myers appears to be a better comp, with his identical 4.03 EqERA, 2.4 BB/9, 6.8 K/9, and 4.2 WARP. The White Sox will be playing in the tightest division in baseball, and will have a fighting chance despite a projection of just 73 wins. If they do defy the odds and play themselves into October baseball, you can bet that the 24-year-old John Danks will have played a starring role in the production, silencing his critics in much the same way that his cutter silences opposing bats.

Eric Seidman is a contributor to Baseball Prospectus. You can contact Eric by clicking here.