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One hot month has David Peralta turning in a career year

The Diamondbacks outfielder is one underrated player.

Los Angeles Angels of Anaheim v Arizona Diamondbacks Photo by Christian Petersen/Getty Images

Mookie Betts, Mike Trout, J.D. Martinez, Aaron Judge, Lorenzo Cain, Andrew Benintendi, and Giancarlo Stanton. These are the only seven outfielders that have been better than Diamondbacks left fielder David Peralta in fWAR. Peralta is in no way a hidden gem, but finds himself consistently under-the-radar compared to baseball’s marquee names.

A former pitcher, minor league release, and independent baseball player, Peralta has a great story that is well known. He’s been a well established outfielder in the majors since 2014, rotating between good and great seasons. Narrowing things down a bit, he’s in no question baseball’s hottest hitter at the moment. No player in the month of August is displaying a higher batting average, ISO, slugging percentage, or wRC+ for the month. Additionally, no player has accumulated more fWAR this month (his teammate Paul Goldschmidt is the closest one).

Top wRC+ in August

Name Team PA wRC+
Name Team PA wRC+
David Peralta Diamondbacks 75 266
Paul Goldschmidt Diamondbacks 83 234
Justin Turner Dodgers 81 219
J.D. Martinez Red Sox 89 218
Ronald Acuna Braves 98 212
Joey Gallo Rangers 78 200
Khris Davis Athletics 83 198
Giancarlo Stanton Yankees 96 197
Tyler White Astros 59 197
Mallex Smith Rays 85 192
Bryce Harper Nationals 90 184
Jose Abreu White Sox 79 179
Mookie Betts Red Sox 93 177
Xander Bogaerts Red Sox 73 176
Marwin Gonzalez Astros 76 173
Willy Adames Rays 75 170
Justin Upton Angels 70 163
Cody Bellinger Dodgers 81 162
Anthony Rizzo Cubs 85 162
Mitch Haniger Mariners 95 159
Qualified hitters FanGraphs

Putting this month into perspective for his career, he’s in the middle of the best month of his major league career and it isn’t even close.

David Peralta wRC+ by month

Season Month Team PA wRC+
Season Month Team PA wRC+
2018 Aug ARI 75 266.1
2018 Jun ARI 115 180.5
2015 Jul ARI 88 176.8
2015 Aug ARI 105 164.4
2015 Sept/Oct ARI 92 147.0
2018 Mar/Apr ARI 111 144.5
2014 Jul ARI 92 131.9
2017 Mar/Apr ARI 102 128.3
2015 Mar/Apr ARI 52 125.9
2017 Jun ARI 98 123.5
2016 May ARI 24 115.1
2014 Aug ARI 111 106.8
2017 Aug ARI 102 106.8
2015 May ARI 85 103.4
2014 Jun ARI 96 103.3
2018 Jul ARI 88 98.0
2015 Jun ARI 95 97.1
2017 Jul ARI 88 92.2
2016 Mar/Apr ARI 110 90.4
2017 May ARI 84 86.7
2014 Sept/Oct ARI 49 85.0
2017 Sept/Oct ARI 103 81.2
2016 Jun ARI 25 67.8
2018 May ARI 100 47.9
2016 Aug ARI 17 44.7
2016 Jul ARI 7 27.8
(2014-) FanGraphs

Admittedly, there’s an easy-to-find culprit for this surge in offensive production. He’s just simply hitting the ball harder. No player has a higher hard-hit rate this month than his mark of 66.1 percent (Kole Calhoun is next closest at 60.3 percent, making the difference between first and second greater than the difference between second and sixth). Adding in an improved K-rate and you’re looking at the recipe for a mammoth month.

So where is this sudden improvement in peripherals coming from? A change in strategy or mechanics? Well, it looks like the main source of the increased hard-contact is launch angle. In years past, Peralta wasn’t exactly a poster child for an ideal launch angle, consistently posting GB-rates greater than 50 percent. Now, he hasn’t really joined the infamous fly-ball revolution, but he is swinging the bat on a more ideal plane.

A 12-degree launch angle isn’t going to give you elite power numbers over a season, but it’s a major improvement on say a seven-degree one. He’s just avoiding the bad launch angles more.

To try and gauge this, I found the average wOBA on batted balls hit at or less than a zero-degree launch angle. As expected, it was low, standing at .164. I then found the percentage of batted balls that player hit at said launch angle. Lowering the minimum to 50 results, only 30 players out of 241 total hit at that range of launch angle more than David Peralta in that time. Performing the same exercise for just the single month of August, Peralta ranked 150th out of 247 batters in the negative launch angle-rate.

Looking on the flip side, I flipped the launch angle range to greater than 10 degrees (which has a league-average wOBA of .471). At this rate of launch angle range, Peralta ranked 299th out of 334 hitters with 50 results (beginning of the season to end of July). In the month of August, he’s been above-average, ranking 144th out of 328 hitters, minimum 10 results. Getting in a swing plane groove has Peralta turning in the best month of his career, crushing baseballs with the best of them this month.

August xwOBA Leaders

Player Name xwOBA
Player Name xwOBA
Ryan Zimmerman 0.513
Ronald Acuna Jr. 0.512
Steve Pearce 0.507
David Peralta 0.503
Paul Goldschmidt 0.497
Grayson Greiner 0.484
Ryan Braun 0.483
Jake Marisnick 0.475
Khris Davis 0.468
Kyle Higashioka 0.460
Minimum 50 results Baseball Savant

One hot month is going to do the majority of the work in what should be a career year for David Peralta. A key cog in the Diamondbacks success- a team that’s fighting for an NL West title- they’ve been playing relatively good baseball the past month (only the Red Sox and Cardinals have had a better team wRC+ this month). If Peralta can continue at least some of this success, the Diamondbacks could be looking at a major boost in their postseason odds.


Patrick Brennan loves to research pitchers and minor leaguers with data. You can find additional work of his at Royals Review and Royals Farm Report. You can also find him on Twitter @paintingcorner.