Reintroducing David Peralta, Underrated Triples Machine

I’m always looking for new angles on National League outfielders. There are only so many of them, and only so many things can be said about the same few juggernauts.

For example, I discovered just now that Randal Grichuk has recorded the fourth-highest wins above replacement (WAR) per plate appearance for NL outfielders behind only Bryce Harper, Giancarlo Stanton and Andrew McCutchen. It certainly surprised me, and while that’s a storyline in itself, Karl de Vries assessed Grichuk here last month, highlighting reasons for optimism and concern. (For example, his batted ball profile validates his power display but thinks his batting average deserves to drop around 45 points.)

In this same vein, it may surprise you to know the infrequently discussed David Peralta ranks seventh in WAR per plate appearance among NL outfielders with as many plate appearances as him (275) and 10th in aggregate WAR. Those figures account for his defense that, according to the metrics, rates average at best, so his value is driven primarily by his bat.

I barely knew about Peralta in March when I assembled my first iteration of tiered rankings and thus left him off the list, only to have several commenters alert me of his omission. Consider this my attempt to make amends.

Peralta exhibits his fair share of peculiarities, perhaps the most notable being his isolated power (ISO) relative to his home run output. He hits extra-base hits by the truckload, helping explain why he ranks sixth in runs batted in (RBI) per plate appearance of those with at least 275 PAs despite his inherent lack of a slugger’s profile or pedigree. My expected ISO (xISO) equations, however, considers the gap power a mirage, pegging Peralta for an ISO almost 40 points below his current level.

But Peralta is fast, capably demonstrating he can stretch any hit into additional bases. He shares the NL outfield lead with Ben Revere for most triples (13) since the start of 2014 — except it took Peralta 362 fewer at-bats to reach the pinnacle. Disregarding league or defensive position, only five players hit more triples than Peralta in that time span, and only Kevin Kiermaier hits them more frequently. Point is, Peralta’s may perfectly blend speed and gap power to occasionally stretch a single into a double or a double into a triple, padding his slugging percentage appropriately.

Moreover, given his speed and modest ability to spray the ball to all fields, my expected batting average on balls in play (xBABIP) equation thinks Peralta has experienced some bad luck on batted balls. His .335 xBABIP calls for five more hits, boosting his batting average by 20-or-so points. I’m sure if he was batting .287 rather than .267, he’d be owned in more than a measly 10 percent of Yahoo! leagues.

Perhaps most impressive, however, is Peralta’s vastly improved walk rate (BB%) courtesy of a much sharper batting eye. In 2014, his 38.3-percent chase rate (O-Swing%) ranked among the worst in the league for hitters with at least 100 PAs. And the league knew, too: with a zone rate (Zone%) of 40.3 percent, only 21 (of 443) hitters saw more pitches outside the zone than Peralta. He has since made great strides, lumping off a quarter of his chase rate in 2015 — the third-largest percentage-point decrease this year behind Charlie Blackmon and Manny Machado. Peralta has capitalized on opposing pitchers’ tendencies to avoid the zone when facing him, contributing to a 2015 walk rate more than double its 2014 level.

Peralta’s augmented plate discipline vaults him from talented bench piece to legitimate all-around contributor. His production isn’t flashy, but he could reasonably finish the season with a .285/.360/.470 triple-slash alongside double-digit home runs and stolen bases. Considering he shares the outfield with A.J. Pollock, Yasmany Tomas and, eventually, Ender Inciarte when he returns from the disabled list, I’m inclined to think the Diamondbacks’ outfield may be among the, if not absolutely the, most underrated outfield in baseball.