Raising Aces: Dallas Keuchel vs. Masahiro Tanaka

One could hardly imagine a more disparate matchup than that which confronts us today, the first day of the MLB postseason. The ancient Yankees take on the upstart Astros in a series that has a bit of a Star Wars feel, what with the young rebels taking on the Evil Empire. Playing the Luke Skywalker role will be Dallas Keuchel, coincidentally a young master of pitching who discovered his own affinity for the craft a bit late in the typical cycle of development. He is opposed by Masahiro Tanaka, a pitcher whose mastery of the force has allowed him to manipulate the flight path of baseballs that seem to disappear on opposing batters. Let's breakdown the specifics of this Wild Card matchup.

The Stats

Keuchel

Keuchel has continued to improve throughout his major-league tenure, and the southpaw upped his K rate from 18 percent in his breakout 2014 to 24 percent this year. The punchouts have helium when further breaking down this season as well, with a 21.3-percent K rate in the first half shooting up to 27.1 percent in his 95 innings since the break.

Season Stats

GS	IP	ERA	H%	HR%	BB%	K%
33	232.0	2.48	20.3%	1.9%	5.6%	23.7%

Keuchel led the AL in innings and batters faced, with 911. His ERA was 0.03 off of leader David Price, the title surrendered when he gave up nine runs to the Rangers on September 16th to tack 0.35 runs onto his final line. It was by far his worst start of the season, and the only game of the second half in which he gave up more than three earned runs. In fact, it was the only time this season (out off 33 total starts) that the consistent Keuchel tossed fewer than six full frames. It was his second straight year with an ERA under 3.00, and the southpaw lopped a half-run off of his ERA from last season. He gave up just 17 homers this season for a 1.9 percent frequency, a mark that would be considered very low if not for the fact that he cracked it with a 1.4 percent rate last season. Seven of those 17 home runs came in September, thanks to a pair of three-homer ballgames in the season's final month.

Tanaka

It has been a very different year for Tanaka, who has pitched this season through a torn UCL that had some (including this evaluator) wondering if he could make it through the first half of the season, let alone lead the pinstripes back into the postseason.

Season Stats

GS	IP	ERA	H%	HR%	BB%	K%
24	154.0	3.51	20.7%	4.1%	4.4%	22.8%

The run prevention leaves something to be desired, but the strike-zone control numbers are beyond impressive, including a K-to-walk ratio better than five. This actually represents a step away from dominance when compared to last season's pace, which included a 26 percent K rate and a free-pass frequency of just 2.8 percent. He has resorted to instigating more contact this season, and the largest disparity between 2014 and '15 is the escalated homer rate; last season he coughed up 15 bombs in 136 innings, and this year the pace has ratcheted up by 50 percent, with 25 homers surrendered in 154 innings of work. For most of the campaign, Tanaka lacked the dominance that he flashed last season, but he has come on like gangbusters in three of his final four starts, tossing his first start of the year with double-digit strikeouts, and shutting down the powerful offenses of the Blue Jays, Orioles, and Mets.

The Stuff

Keuchel

Pitch Type	Count	Freq	Velo (mph)	pfx HMov (in.)	pfx VMov (in.)	H. Rel (ft.)	V. Rel (ft.)
Fourseam	233	6.88%	90.36	3.02	9.43	0.74	6.39
Sinker	1681	49.63%	90.47	8.02	5.27	0.87	6.34
Change	468	13.82%	79.76	8.84	5.50	0.80	6.25
Slider	671	19.81%	80.19	-5.75	-2.11	0.81	6.22
Cutter	334	9.86%	87.34	0.32	4.36	0.70	6.36

The centerpiece of Keuchel's game is a sinking fastball that he brings to the plate on half of his pitches, inducing groundballs by the bushel (a 62 percent grounder rate this season). Once the weakest link in his statistical profile, his strikeouts have really come on strong, fueled by a wicked slider that has coaxed a rate of 43.4 percent whiffs-per-swing from opposing batters this season and has been responsible for more strikeouts than any other pitch in his repertoire.

Interestingly, the biggest leap in his whiff rate over the second half of the season came on his fastball variations, which shot up to more than 20 percent overall, including a jump of five percentage points for his bread-and-butter sinker. Those five points might not sound like much on the surface, but when comparing the 15 percent whiff rate of the first half with his 20 percent rate of the second, the disparity rings loudly for a pitcher whose secondaries induced empty swings at roughly the same rate as before.

Tanaka

Pitch Type	Count	Freq	Velo (mph)	pfx HMov (in.)	pfx VMov (in.)	H. Rel (ft.)	V. Rel (ft.)
Fourseam	424	18.69%	92.81	-5.74	9.59	-2.16	5.48
Sinker	313	13.79%	91.68	-8.70	5.99	-2.19	5.45
Slider	499	21.99%	84.38	1.68	1.95	-2.30	5.44
Curve	166	7.32%	77.08	4.26	-4.16	-2.16	5.57
Cutter	248	10.93%	89.75	-1.80	6.44	-2.27	5.39
Split	618	27.24%	88.01	-6.41	2.19	-2.15	5.52

The vast majority of Tanaka's pitches fall within a narrow velocity band, and the key to his success has been keeping the ball down. With a trap-door split and a late-diving slider, Tanaka's ability to live below the hard deck of the strike zone is a major determinant of his success, but when those pitches aren't getting dirty then he runs the risk of batters getting underneath and lifting them out of the yard.

For all the talk about how his velocity might be compromised by his injured wing, Tanaka has actually exceeded the average pitch speed of last season, though he has leaned more heavily toward the cutter and curve this year in lieu of fastballs. The greater implication of his injury has been the right-hander's reduced pitch command this season, which has been a culprit in the increase of isolated power on both his slider and split in 2015, including an ISO greater than .120 on both pitch types. Another indication of his struggles to keep the ball under bats this season is Tanaka's rate of whiffs-per-swing, which has fallen from the 2014 marks of 39.5 percent on the slider and 46.0 percent on the splitter to this season's marks of 32.6 and 33.5 percent, respectively.

The Mechanics

Keuchel

Mechanics Report Card

Balance	60
Momentum	55
Torque	50
Posture	50
Repetition	60
Overall	B-

For an explanation on the grading system for pitching mechanics, please consult this pair of articles.

Keuchel has excellent balance that is maintained well in all three planes of space, with only a small vertical drop and a slight hunch to the first-base side during the stride phase; that's all that keeps him from an elite grade for stability. He invokes a bit of spine-tilt as the throwing arm comes through in internal rotation, culminating in league-average posture at release point, but this is an area where Keuchel has room for improvement to further enhance his pitch command in the future.

The biggest change to Keuchel's delivery over the past couple of years has been to his momentum. Once considered slow (I gave him a 35 grade in the 2014 Starting Pitcher Guide), Keuchel's burst to the plate has become an above-average attribute that flashes plus on occasion. The delivery starts slowly, but he has a stark gear change after max leg lift and has upped his overall pace to the plate from the 35 of two years ago to last season's 45. He now has even extra burst in 2015, resulting in an above-average charge that the southpaw has found easier to repeat on a pitch-by-pitch basis.

Tanaka

Mechanics Report Card

Balance	55
Momentum	45
Torque	50
Posture	50
Repetition	60
Overall	B-

Tanaka lacks the mechanical baselines that one would expect from a control artist, at least in terms of maintaining balance throughout the delivery. He has actually made improvements in this area in 2015, reducing the vertical drop in his delivery and maintaining a more stable head position throughout the motion, converting the 50-grade balance of last season to the above-average attribute that was on display this year. His balance was already strong in the X- and Z-planes last year, but the reduced drop to his drive has upped the ante of his stability grades. His posture has drifted between above and below average over the past couple of seasons, watching his subpar marks from Japan give way to lesser spine-tilt in his first campaign state-side, only to lose some of those gains this season.

The league-average grade for momentum can be a bit deceiving, as Tanaka has been known to invoke a gear change centered around the top of his delivery, but his burst to the plate was a bit slower this season than it had been in 2014. He almost appeared to slow down during the stride phase of his delivery on some pitches, rather than invoke the gear-change to a bigger burst after leg lift, and the reduced power was responsible for a drop on his report card to below-average levels. His repetition is still considered plus, but the downgrades in momentum and balance have had a ripple effect on his ability to repeat the delivery and command the baseball.