Making Sense of Alex Wood’s Bizarre Stats

When a pitcher starts off a season with a new look, it’s hard to know whether or not you can trust their success. That’s especially true when that “new look” involves a change that we generally assume to be negative.

This is precisely the situation we find ourselves in with regard to Alex Wood. The Dodgers’ lefty has compiled a career-high K-BB% (23.3 percentage points) through four starts, even though his average sinker velocity is more than 3 mph lower than where it was last April. He seems to be carrying a red flag with the words “SELL HIGH” boldly emblazoned on it, but could it be that he has found a new way to succeed?

The task of assessing Wood’s value may not seem all that daunting, as his decreased velocity is not exactly a new development. After starting off the 2017 season with an average sinker velocity in the 93-94 mph range, Wood was throwing with steadily less velocity as the season wore on. After the All-Star break, Wood’s sinker was hovering around 91 mph, and in an Aug. 9 start at the Diamondbacks, he rebounded to 92.3 mph. He has made 11 starts since then, and he has yet to eclipse a 92 mph average in any of them.

Ever since that Aug. 9 start, Wood has not rebounded in terms of ERA or strikeout rate, but his WHIP has dropped slightly from 1.02 to 1.00. Over his four starts this season, Wood has allowed only one home run and one walk, and the latter of those came in the sixth inning of Tuesday night’s outing against the Padres. His 2018 K-rate is only two percentage points behind his mark from his first 20 starts of 2017, as is shown in the table below.

On the surface, it appears that Wood has made only a small sacrifice in strikeouts, while being steady in his ability to limit walks and exit velocity. Even the spike in his home run ratio from late last season doesn’t look so bad when you realize it coincided with a brief dip in ground ball rate.

What remains confusing about Wood’s trends is that, during his limited sample of innings this season, he is no longer one of the majors’ better pitchers in terms of freezing batters. Of the 75 pitchers who threw at least 150 innings a year ago, Wood’s Z-Swing rate of 63.8 percent was the 15th-lowest. So far in 2018, he has a 70.4 percent Z-Swing% that is the 12th-highest out of 83 qualified starters. Wood has slowed down his pace of called strikes, but he hasn’t compensated by getting more swings and misses.

Also, Wood’s Zone% has dropped from 43.1 percent to 40.7 percent, which makes it hard to grasp his lack of walks, especially since his O-Swing% of 37.1 percent is only one percentage point higher than last year’s mark. Given how much more often opponents are taking hacks against Wood when he’s pitching in the zone (which seems like a likely result of pitching at a lower velocity), and how he is throwing fewer strikes, it’s hard to see how Wood will maintain his current strikeout and walk rates.

For a reference point for the worst-case scenario, take a gander at what’s happening to Aaron Nola in his starts to date. Like Wood, Nola has seen a sizable spike in his Z-Swing% and a even larger drop in his Zone%. After four starts, Nola has a K-BB% of just 6.5 percentage points. Granted, Nola is inducing swinging strikes at a meager 6.4 percent rate, which highlights how important it is for Wood to maintain his current 11.5 percent whiff rate in the face of lower velocity.

Even if his strikeout and walk rates regress, it doesn’t necessarily mean that Wood’s ERA will rise or even settle near its current 3.91 mark. He currently owns a ridiculously-low 38.5 percent strand rate. Toss in Wood’s current .227 BABIP, and you have a strong contender for the weirdest stat line of the season’s first three weeks. Whereas there is no reason to think Wood will strand runners at a far-below-normal rate, given his propensity for getting grounders and low-velocity batted balls, he could continue to beat the odds on BABIP, if not quite at his current pace.

Given the strangeness of Wood’s stats and the still-small sample, the best approach to assessing Wood is to wait and see how his season progresses. However, the current signs point to strikeout and WHIP regression, but an ERA that might actually drop into the mid-3.00s as Wood strands more runners.