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Buster Posey becomes selectively aggressive

Thanks to a retooled approach, San Francisco's star backstop hasn't missed a beat in 2015.

Posey hasn't turned into his ex-teammate Pablo Sandoval.
Posey hasn't turned into his ex-teammate Pablo Sandoval.
Ed Szczepanski-USA TODAY Sports

When the season wraps up, the National League MVP crown will, in all likelihood, rest upon Bryce Harper's magnificent locks. His fWAR of 8.3 paces the Senior Circuit by a mile — Joey Votto, in second place, trails him by nearly two full wins. Even if the Nationals continue their epic collapse, Harper's incredible 2015 campaign should correctly receive the honors come year's end.

Harper's dominance shouldn't obscure the exquisite play of several men who previously earned the award. Votto, the 2010 winner, has reached base in every plate appearance in the second half (give or take). Andrew McCutchen, who took home the trophy in 2013, has thoroughly eliminated any doubt he created with his early-season slump. And perhaps most unnoticed of all, Buster Posey — the man who has the 2012 MVP award and three rings to his name — has done as well as ever. With sterling defense backing up another outstanding year at the plate, he's accumulated 5.5 wins above a replacement-level player.

In many regards, Posey's offense hasn't differed much from before, and some areas have actually declined. He's taken an unintentional walk in 7.2 percent of his plate appearances, a slight downgrade from his career mark of 7.9 percent. His BABIP has risen marginally, from .329 overall to .334 in 2015, but losses in power negate any benefit of that: He's seen his ISO drop to a all-time low of .159, sizably below the .175 standard he's set for himself. How, then, has he posted a better wRC+ in 2015 (145) than for his career (142)?

It's simple —he's gone down on strikes less often. And by less often, I mean waaay less often:


Unlike many other formidable hitters, he's never piled up a ton of strikeouts, but this year has been something else entirely. Only two other qualified players in the NL best his 8.8 percent strikeout rate, and suffice to say that Daniel Murphy and Andrelton Simmons don't hit the ball as hard as Posey does. This combination of very few strikeouts and superb results when making contact has once again made Posey an elite contributor with the bat.

When most fans (myself included) notice that a player has cut down on his strikeouts, they immediately assume that he's whiffed less often. Interestingly enough, that hasn't applied to Posey. At 6.6 percent, his current swinging strike rate matches his career 6.9 percent figure. Thus, his reduction in strikeouts has come from his rate of looking strikes, which have fallen to a career-low 15.2 percent of the pitches he's seen. Posey has paired his already-elite contact ability with a newfound sense of aggression, resulting in a dramatically decreased strikeout rate.

Perhaps most impressively, Posey has retained his discipline at the plate. As his Z-Swing% has climbed nearly eight percentage points relative to career marks, his O-Swing% has increased by less than half that:

Year(s) O-Swing% Z-Swing% Zone%
2015 28.8% 69.6% 46.9%
Career 26.1% 61.8% 49.0%

The opposition has begun to pitch around Posey to a greater extent, further aiding him in his quest to avoid the K. This sort of disparity in offering at pitches doesn't come around too often. Among qualified NL hitters, only four — Posey, McCutchen, Kris Bryant, and Jhonny Peralta — own an O-Swing% below 30 percent and a Z-Swing% above 69 percent. Plus, the latter three names have each swung and missed more than the league average, so Posey's ability to make bat meet ball further sets him apart. His aberrationally low strikeout rate has some equally unusual skill behind it.

A glance at Posey's plot profiles show that he's mostly swung more often at high pitches:


Posey has taken a hack at 63.3 percent of balls in the lower third of the strike zone, which lines up fairly cleanly with the 60.3 percent clip he's established in his major-league tenure. By contrast, Posey has increased his swing rate at pitches up in the zone by a much larger extent — the upper two-thirds of the plate have seen their swing rate spike from 65.9 percent to 74.4 percent. Although this means that Posey has chased his fair share of high pitches, he's compensated for that by continuing to lay off balls in the dirt. In this way, he's managed to keep avoiding unnecessary strikes, while cutting down on the called ones.

Even when he maintained a strikeout rate in the double digits, Posey still raked. Now that he's swinging more than ever at hittable pitches, perhaps he'll regain his power stroke. For what it's worth, he presently possesses the highest rate of hard contact in his career, at 35.8 percent. He's no Harper, but hurlers still fear Posey. Whereas they once hoped to catch him looking, he's erased that strategy. If Posey manages to keep this up for a few more years, he could add another trophy to his hardware collection.

. . .

All data as of Tuesday, September 8th.

Ryan Romano is an editor for Beyond the Box Score. He also writes about the Orioles on Camden Depot (and on Camden Chat that one time) and about the Brewers on BP Milwaukee.