AJ Pollock is an Offensive Force, For Now

A.J. Pollock is becoming quite the weapon at the plate. As you’ve probably noticed, his production has been way up over the last few weeks as he’s sporting a .315/.364/.546 line for the Diamondbacks. His 148 wRC+  is tied for first (with Paul Goldschmidt) on the team and tied for 11th in the National League (min. 140 PA’s). Considering he’s only amassed 130 at-bats this year (through 5/19), he’s been incredibly valuable. With advanced metrics in mind, however, I have a couple of questions. Where is this increased production coming from and is it sustainable?

General Batting

Comparing Pollock’s 2013 campaign to what he’s done this year, we can see universal progress. His average, on-base percentage and slugging numbers are all way up. His weighted on-base average (wOBA) is largely an amalgamation of these factors and shows incredible advancement from the year prior. Take a look at the table below.

If this is where we stopped our search, as so many people do, we’d be left with one conclusion: AJ Pollock is one of the best baseball players in the National League irrespective of position. But is that really the case? Let’s dig deeper.

Splits

Pollock is a right-handed batter who struggled some with same-sided pitching last year. He wasn’t horrendous by any means, but there was a clear gap in production between facing lefties and righties. This was to be expected as most hitters show a similar split and his was very average. Fast forward to 2014 and we see something weird. He’s no longer struggling against right-handed pitchers. Instead, he’s mashing them.

So far, he’s completely reversed his platoon split. AJ’s still solid against lefties, but he’s punished right handed pitchers in 2014. We could see growth from him as 2013 wore on and now he’s on a tear. But the tear he’s on, where he’s simply abusing same-sided pitching, was not expected. In fact, I’m very skeptical that it holds up as these types of huge shifts are often just sample-size driven blips. It’s definitely something to watch, however, and if the change is something that he can repeat, even if not to this magnitude, he’d immediately become a much more balanced hitter.

Plate Discipline

At the dish, Pollock has always been solid. He’s a relatively patient hitter who hasn’t expanded the zone at an alarming rate in the past. He’s willing to take pitches in the zone, but swings when he feels like he can barrel something up. All in all, there haven’t been any warning signs. That is until this year, where’s he’s expanding the zone at much higher rate (O-Swing%). As you’d guess, he’s not making a ton of contact on those out-of-the-zone pitches, which is why hitters tend to avoid swinging at them in the first place. These added whiffs have driven down his cumulative contact rate (Contact%)

This doesn’t mean that Pollock has turned into a bad hitter, it’s just that he’s shown a relatively new trend of expanding the zone. This would hint at some additional aggressiveness at the plate, which may be working in his favor for now. If pitchers decided to exploit this trend, however, he could start seeing fewer pitches in the zone and it would be up to him to take those pitches, not swing and presumably miss on them. Given that Pollock is doing some serious damage of late, I’d fully expect hurlers to start pitching him a little less directly as he’s demonstrated an ability to make quality contact on pitches in the zone.

Luck

My least favorite variable here is luck. Has AJ simply been lucky this year? Well, that’s awfully hard to say. What we do know is that his BABIP is exceedingly and unsustainably high at .371. He’s a good runner who makes good contact, and those things certainly help, but his current BABIP will never hold up over the entire course of the season. What may be even more surprising is that his line drive rate is currently way down (12.7%) and his fly ball rate is way up (38.2%), which one would think would result in more outs given that fly balls are the easiest batted balls to turn into outs for an opposing defense. Of course, some of those fly balls have ended up in the outfield bleachers for AJ,  but this yet another sign that he’s been lucky (balls falling into the gaps) rather than simply dominant.

What It All Means

Players get hot and players go cold. Pollock is clearly in the first category at the moment. While he’s got wonky splits, some potentially troublesome plate discipline trends and has been lucky on the year, the D-backs faithful surely aren’t complaining. The 2009 first-rounder (17th overall) is succeeding and helping to drive the team in the process. He’s been the team’s best option at the top of the order (121 wRC+ when leading off), but also continues to be excellent with runners in scoring position (110 wRC+ in 2013, 189 wRC+ in 2014). While we shouldn’t expect the current pace to hold up, we should all sit back and enjoy the show he’s putting on.