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Kolten Wong’s second-half adjustment

An analysis of where Kolten improved in the second half of the season.

Atlanta Braves v St Louis Cardinals Photo by Dilip Vishwanat/Getty Images

Let’s get this out of the way: Wong is a strong defender. Over his career, Ultimate Zone Rating (UZR, one of the two major public defensive metrics) rates Wong four runs above the average second basemen per year’s worth of innings at second base. Defensive Runs Saved (DSR, the other major public defensive metric) likes him twice as much. He’s also a strong base-runner. For his career, he’s averaged 4.3 runs above average per 600 plate appearances.

He’s also not bad in non-contact situations. That is, strike outs, unintentional walks, and hit by pitches. Those three situations make up non-contact wOBA, and Kolten Wong placed first among the Cardinals in that stat, thanks to an above average 9.4% walk rate and well-below average 14.4% strikeout rate. His defense, base-running, ability to work walks and limit strike outs all make him a useful player even with his struggles with results in contact. Remember that, because from here on out, we’ll mostly be talking about that weak contact.

For his career, Wong has been poor at getting hits on balls in play as well as hitting for power. If you visit this blog often you no doubt are aware of Wong’s struggles in 2016. If not, here’s a graph of his 25-game rolling wRC+ courtesy of :

Wong had a very rough beginning of the season. At some point though, he picked up the production and ended the season in a much better place. That last valley between the 300 and 350 marks occurred on June 30th. Let’s look at Wong’s stats in 2016, separated into before and after that date:

Through June, Wong was hitting at Kozmanian-level lows. From July on though, He hit just a smidge above average. Combining his second-half wRC+ with his career rates in base-running and defense makes a 3 WAR player, which is solidly in “good” territory.

The big difference for Wong was the power. In the first half, Wong had an ISO 41 points lower than Jon Jay’s career mark. In the second half, his ISO was 22 points above league average. That was enough to make Wong a slightly above-average hitter despite a BABIP (batting average on balls in play) much lower than average (.300).

Chief of concern to me, is finding out what lead to Wong’s show of above-average power. This graph sums it up extremely well:

Throughout the second half of the year, Kolten’s Fly Ball percentage (FB%), Pull percentage (Pull%), and Hard hit percentage (Hard%) all trended up. This makes sense: Wong’s pulling the ball more often, hitting in the air more often, and hitting it hard more often. Those three things simultaneously led to higher power output. Going back to the same June 30th boundary, here’s his batted ball stats, again courtesy of Fangraphs:

Wong hit more line drives and flies, and less grounders. He also managed a lower infield fly per fly ball rate (IFFB%), which is great considering the obvious conscious effort to hit more flies. The increase in Pull% is much more marginal than it might seem in the graph above. Still, it is at a dangerously high level. Last year, Wong was shifted against in over 40% of his plate appearances, which explains part of the low BABIP.

Wong’s Home Run per Fly Ball rate (HR/FB%) went from an anemic 2.4% to a still below average 8.5% (average in 2016 was 12.4%). His ISO was boosted more by extra base hits in play: six doubles and five triples in 177 plate appearances.

Next, I wanted to analyze his batted ball authority. Using the Statcast-based leaderboards at, here’s a breakdown of Kolten Wong’s average Exit Velocity (the velocity the ball leaves the bat at, in terms of MPH) by batted ball type:

Wong had virtually identical average Exit Velocity in both halves. However, he did successfully increase his average Fly Ball and Line Drive Exit Velocity (avg FB/LD%) by two and half MPH. He increased his Fly balls and Line Drives, while increasing how hard he hits them. This is looking a whole lot like a successful adjustment.

Why should you be interested in avg FB/LD EV? That’s because it has so far been more predictive of future HR/FB% than HR/FB% itself. Statcast started collecting data in 2015. Here’s a graph of each hitter with 30 Statcast-recorded batted balls in 2015 as well as at least 60 plate appearances in 2016:

The R-squared value is .402, meaning the average fly ball and line drive velocity explains 40% of his HR/FB% in the following season. Let’s compare that with HR/FB%. Here’s every instance where a player had 60 plate appearances in back to back seasons since 2006, and their HR/FB% in each:

As you see, the R-squared value is lower, and considerably so. Average fly ball and line drive velocity is nearly 20% more predictive of HR/FB% than HR/FB% itself. Using the best fit-line above, Wong’s expected HR/FB% in the first half was 2.7%, pretty close to the actual rate. in the second half though, it was 6.6%, lower than his actual rate of 8.5%. With Wong hitting just four homers, we’re talking about a difference of one home run. Not all that bad really.

This did have repercussions for his BABIP though. In past posts, I’ve used the Statcast data at to calculated an expected BABIP based on each batted ball’s Exit Velocity and Launch Angle (the angle that the ball leaves the bat) and the historical chances that each of those batted balls is a hit. In the first half, Wong scored a .294. In the second half, it dropped to .283. However, those calculations don’t take into account that he’s shifted against often.

It’s hard to know how to feel about these changes. On the one hand, Wong increased his power, while sustaining his advantage in terms of walks and strikeouts, and only taking a small drop-off in BABIP. The Statcast data indicates that he deserved one less homer than his total, but even accounting for that, we’re looking at a better hitter.

At the same time, the Statcast numbers paint the picture pretty clearly: Wong’s not the guy that should be swinging for the fences. However, Major League Baseball is not the best place and time to massively overhaul a swing. Wong’s always been the guy to swing for the fences, at least he’s doubling down on the strategy by making successful adjustments. He may be pulling the ball more often, which makes him more susceptible to the shift when he puts the ball on the ground. But this adjustment also came with a much reduced Ground Ball percentage, meaning the shift will matter less.

Of course, as you’ve read this, you might have remembered that Kolten Wong has talked about changing his swing this off-season. The money quote from Kolten goes: “Shortening my swing. Rather hit line drives than home runs.” Ideally, more line drives, and a hit to all fields approach sounds great for Kolten. He just hasn’t shown the ability to drive fly balls at a necessary level to hit for above-average power, and at this point he’s unlikely to discover it. Again though, changing swings is tough at this point in the game.

I’m not a scout, I can’t tell you if shortening his swing will create more line drives. The people I trust on those types of things have said Kolten doesn’t have a long swing, and point to his low strikeout and high contact rates as evidence. So right off the bat, this sounds worrisome that Kolten might do more harm than good by messing with his swing. Of course, it’s just a single quote and you don’t want to take things too literally without context.

At 26 years old, Wong probably isn’t going to re-create himself as a completely different hitter. Attempting to do so may have unintentional consequences that make him worse than before. Kolten Wong needs to be the best version of Kolten Wong that he can realistically be. The adjustment he already made speaks to this. He’s a guy that swings for fences, that increased his ability to hit fly balls and line drives hard. Sure, he still doesn’t hit them all that hard, but it’s an improvement. That’s a much easier adjustment than completely changing who you are as a hitter, as ideal as that attempted change may seem.

Again, Kolten Wong is an above-average defender at an above-average spot on the defensive spectrum. He’s a well-above average runner, who walks at an above-average rate and strikes out much less than average. He makes weak contact, but the overall game is still a tick above average. In the second-half, he made some real adjustments to make his contact less weak. Let’s see if he can keep it going in 2017.