The Arizona Diamondbacks second-half struggles: a per-player approach

Before we get to individual players, let’s take a quick look at overall team performance as measured by fWAR. [Note: I will be using Fangraphs WAR throughout, simply because they offer WAR splits by first- and second-half, which Baseball Reference do not]. How close does fWAR come to predicting the actual number of wins by the 2017 D-backs in each half?

First half. There were 89 games played in the first half. A replacement level team would have a .294 winning percentage = 26.2 wins. Add on the first-half fWAR of our hitters (11.6) and pitchers (14.1) and you get 51.9 wins. The actual record in the first half was 53-36, pretty close to expectations. Second half. Going into play today, there have been 30 games played, so the replacement level team would have 8.8 wins. Again, adding the second-half fWAR for hitters (3.5) and pitchers (also 3.5), you get 15.8 expected wins. But the team is actually only 13-17. This tends to confirm Sean’s conclusion that the team hasn’t got the results their performance deserves.

To see which players have had their production change, for better or worse, I’ve normalized both first- and second-half fWAR to be per 81 games. I’ve set the bar for inclusion of position players to being those with at least 100 first-half PA and 40 second-half PA. For pitchers, it’s 20 IP and 8 IP respectively. This does exclude some significant contribution - particularly obvious are J.D. Martinez, Ketel Marte and Yasmany Tomas. But we’re looking for differences in performance. The chart below is thus in descending order. A positive figure means a player was more productive in the first half; a negative one means they have been better in the second half.

There are perhaps some mitigating factors, such as injury. But it’s also clear that Chris Owings’ had been struggling for some time before he was hit by a pitch on July 30. He ended June at an OPS of .829, but over 22 games in the month of July until the broken hand, his line was .169/.188/.253, for an OPS of .441. He had 85 plate-appearances, 25 strikeouts and one walk. Brandon Drury’s numbers similarly reflect his struggles since the calendar turned from June. At that point, his OPS was .802, but since then he has had his share of issues (.222/.308/.333), leading to the recent loss of his everyday starting job at second-base.

Andrew Chafin and Robbie Ray I’m less concerned about, because in both cases we are talking a sample size of only a dozen innings or so. In the former’s case, it’s also partly a result of him being so good (1.80 ERA) in the first-half, that his second-half performance (3.86 ERA) seems mediocre in comparison. Rounding out the five with the largest drop is the Internet’s favorite scapecoat, Chris Herrmann. He wasn’t very productive in the first half, and - while there may be no small component of bad luck - has fallen further since, batting .086 in the last month. Further back, there are quite a few who have fallen short by smaller amounts; it all adds up, though...

It isn’t all bad news, however. We have the positive second-half contributions of Marte, who trails only Goldschmidt for fWAR since the break. And speaking of Goldy, weren’t there those who tried to claim he was “slumping”? He’s actually hitting .343 since the break, with a 1.117 OPS, and is top five in the NL for fWAR. We could all slump like that. Jeff Mathis has also performed much better at the plate. He went into the break a Jackson short of his weight, but has batted .304 since, including an 11-game hitting streak, and with an OBP of .407. Among the pitchers, Zack Godley has continued to impress, and Fernando Rodney’s only meltdown at least came in a non-save situation.

The rest of the way

This is mostly useful, in showing the players from whom we can look to get improvement over the final quarter of the season. Owings probably isn’t coming back, at least not soon enough to make a difference. But if Ray can return, and get back to the quality of performances he showed in the first half, that will be a significant boost over the upcoming 40 games. Figuring out Drury’s struggles would also be helpful, and Jake Lamb getting back to his excellent first-half form (what is this, 2016?). On the other hand, perhaps we should just keep our fingers crossed Goldschmidt continues to carry the team on his back, as he has done offensively for almost the entire season.