The Arizona Diamondbacks’ struggles against left-handed pitching

The Diamondbacks faced left-handed starting pitchers in Los Angeles on Tuesday and Wednesday night, and it did not go well. The team failed to score a run off either of them, and it wasn’t pretty. Over 14 innings from first Clayton Kershaw, and then Alex Wood, Arizona managed just five hits and four walks, with no fewer than 21 strikeouts. It was a tough couple of games, there’s no doubt about. But does it indicate a particular problem for the team - in particular, a potential weakness which could be attacked by an opponent, particularly during a short playoff series? Let’s take a look at the numbers.

Team statistics

The Diamondbacks have certainly performed better against right-handed starters overall. They are 42-23 against them, compared to only 10-10 in games started by a southpaw. Those rank third-best and seventeenth-best in the majors respectively, so it’s clear the team is not doing so well against these left-handed starters. However, it’s worth noting that those starts include some VERY good opponents. Five of them have come against the three left-handers with the lowest ERA (min 50 IP) in the National League this year: Alex Wood, Clayton Kershaw and Gio Gonzalez.

Looking just at batting statistics, the team ranks fourth overall in National League OPS, at .776. Against RHP, that rises to second (.811), while against lefties, we plummet all the way to 14th (.668). A fragment of that drop is to be expected, because batters generally do hit left-handed pitching less well - likely because they see less of it. But the split across the entire league is only 12 OPS points, a tiny fraction of the 108-point gap the Diamondbacks have demonstrated to date. Also of note, our K:BB ratio also goes up sharply, from 2.50 against RHP, to 3.45 against LHP.

Individual stats

The table below shows the stats versus left-handed pitchers for each Diamondback position player, with at least 10 PA in that situation [which excludes, basically, Ketel Marte and Jeremy Hazelbaker]. It’s in descending order of OPS, and left-handed hitters are shown in bold/italics, so they stand out.

You can see that our left-handed hitters in particular have been terrible against their colleagues on the mound. Together, they have posted a collective line of just .164/.227/.262 for a .489 OPS that’s dead-last in the National League. Particularly problematic is perhaps Jake Lamb’s continuing struggles in this department, since he is in the line-up just about every day. At least with the likes of Chris Herrmann, Gregor Blanco, etc. we have some solid platoon alternatives. Which makes it all the more odd those two played last night, while David Peralta (easily our best left-on-left producer this year) and A.J. Pollock sat.

But even among the right-handed hitters, production has been rather muted in a lot of cases. Take Paul Goldschmidt, for example. His OPS’s from 2014-16 against left-handers were highly consistent: 1.115, 1.081 and 1.070. He’s almost three hundred points down on the last figure this season, at .774. He used to destroy them, in a way resembling Godzilla going through Tokyo (hello, Tim Lincecum): this season he has been little more than average against left-handers. I’m open to suggestions about the reason for such a spectacular drop-off. It’s not even as if we have a new hitting coach, Dave Magadan being in his second season with Arizona.

Fixing the problem

Getting the team back healthy may be a good chunk of what’s needed. The return of A.J. Pollock, who has a career .832 OPS against LHP, should help - as soon as he can get back to playing everyday, which doesn’t quite appear to be the case yet. Nick Ahmed and Yasmany Tomas could also be part of the solution. However, the former is some way off, and the latter doesn’t seem to be getting better, and was recently re-diagnosed with a groin strain, rather than tendonitis.

If we’re looking for outside help, Christian Walker would seem the most obvious candidate in the minors. The 26-year-old outfielder has shown good power, with 20 home-runs in 82 games, and an overall .941 OPS. However, he has had his own share of struggles against left-handers, with his line against them .229/.316/.443, and only three home-runs. The same goes with Carlos Rivero, the Aces’ other leading right-hand bat at the moment: he’s also hitting left-handers worse. It almost seems to be a systemic, organizational problem, which is even more bizarre.

It may be that, as the trade deadline approaches, Mike Hazen will be forced to look outside for assistance. Who that might be, and what that would cost us, will remain to be seen. But again, I’m open to suggestions of credible trade targets, who could help the Diamondbacks in the second-half.