Will the new Kolten Wong continue into 2018?

In his fourth season in Major League Baseball in 2017, St. Louis Cardinals second baseman Kolten Wong was, for the first time in his career, above-average as a hitter. By wRC+, Wong scored a 107, which is to say that he was seven percent above league-average for the year.

That it took Wong four years to be above-average at the plate did not mean that he was an insufficient player. Wong had also been an above-average fielder at a premium defensive position and was also a good base runner (endless replays of the worst moment of his professional career aside). But at the plate, Wong had been merely passable—players who contribute as Wong does in non-hitting ways don’t have to be good hitters to justify their Major League existence, but it’s certainly nice when they are good.

Some of Wong’s numbers in 2017 were even less flashy than in previous seasons. His home run power, for one, was at its lowest mark since his 2013 partial season. In 2014, Wong homered in 2.8% of his plate appearances. In 2015, it fell to 1.8%. It dropped once again in 2016, to 1.4%. And in 2017, Wong hit a career low by hitting a home run in fewer than one percent of his plate appearances. On the bases, Wong, who stole 20 bases as a rookie, was efficient but relatively unspectacular, swiping just eight bags.

Wong had a career-high walk rate in 2017, walking in just under 10% of his plate appearances, and while this would have been considered a tremendous breakthrough following walk rates of 4.8% and 5.9% in 2014 and 2015, it was only a marginal improvement from his 9.4% walk rate in 2016. Progress is progress, sure, but Wong went from a career-worst wRC+ of 86 to a career-best wRC+ of 107 in one year, and a moderate uptick in his walk rate (not to mention the decline in his power) could not account for such improvement.

What did happen was Wong’s batting average on balls in play increased by 63 points. While Wong’s 2016 mark was a career low, his high mark in his first three seasons was .296, while his 2017 BABIP stood at .331. At its most basic, BABIP is interpreted as an indicator of luck—a ball in play is simply a ball that had the good fortune of not being directed to a fielder, and thus a high BABIP mark does not reflect talent as much as it reflects fortune. But while BABIP is often based on luck and is thus not sustainable in the long run, there are exceptions to the rule, and dismissing Kolten Wong’s 2017 as an aberration without further examination is more than a bit rash.

Among players with 100 or more batted ball events (defined by MLB as any fair ball or any foul ball that results in an error or out) in 2017, Kolten Wong ranked 306th in average exit velocity (speed at which a ball is hit) of 387 hitters, at 85 miles per hour. In 2016, Wong had an average exit velocity of 85.9 MPH—far from elite (Nelson Cruz led baseball that year at 94.5 MPH/BBE) but better. And in 2015, the first year in which such data is publicly available, Wong’s exit velocity averaged 87.1 MPH.

A huge part of this drop-off is approach: while most batters have zigged towards pummeling every pitcher in the galaxy with all of the dingers, Wong has zagged towards more plate discipline and less power. It’s not an inherently better or worse approach from a production standpoint (aesthetics and personal preference of small ball versus a veritable home run derby aside) but it does lead to questions about sustainability, even if in the case of Kolten Wong, it might make sense. The tall tales of Ichiro Suzuki being capable of hitting 40 home runs if he so desired were always bizarre—if anyone could hit 40 home runs he absolutely should, but Kolten Wong has so far peaked at twelve. This might just be the method by which he can most succeed.

By xwOBA, Kolten Wong tied for 180th out of the 428 players in Major League Baseball with 100 or more plate appearances in 2017—while he is decidedly above the median for Major League Baseball hitters, this is because most of the players near the bottom of the list had fewer plate appearances (unsurprisingly, good players tend to get more playing time). Wong’s xwOBA of .321 is exactly equal to MLB’s total mark of .321. Wong’s xwOBA was 15 points lower than his wOBA—this is far from the biggest gap in baseball, but it is material enough to turn Wong from, in wRC+ terms, a 107 player (slightly above average) to basically a 100 player (completely average).

Six other players tied with Wong by xwOBA last season, and luckily, for the sake of easy comparisons, one of them was fellow St. Louis Cardinal Randal Grichuk. And while Wong’s 2017 was mostly praised at the plate, Grichuk’s led to a brief stint in high-A Palm Beach. The comparisons of Wong and Grichuk are, as even the most casual fan should know, extremely superficial—while Wong has lowered his power and increased his walks, Grichuk has shown the potential to, if he were a full-time starter, hit at least 30 home runs in a season, all while having absolutely dreadful plate discipline.

But Grichuk is an interesting point of comparison in terms of overall value, because even if Grichuk’s actual results had been league-average (his wRC+ stood at 94), he would still have been considered a disappointment because this happened primarily while he played left field, a non-premium defensive position. Defensive and base running value is an enormous part of evaluating a player—it is why Albert Pujols (78 wRC+ as a DH in 2017) was the least valuable player in baseball by FanGraphs Wins Above Replacement and Billy Hamilton (66 wRC+ as an elite center fielder in 2017) was closer to league-average than replacement level.

When Paul DeJong emerged as the Cardinals’ shortstop last season, he was compared to Randal Grichuk several times (here are two examples from this website alone). But since there is a huge difference between a league-average hitting shortstop and a league-average hitting left fielder, this wasn’t necessarily unkind to DeJong. Like DeJong, underlying statistics suggest Kolten Wong may be due for some offensive regression (less dramatic regression, though regression nonetheless), but if it turns out Wong is an average hitter, that is still a very valuable asset at second base.

Wong has been above-average in the field throughout his career, and while 2017 was his first below-average season in the field, a single season’s worth of fielding data is cause for, at most, minor concern—in all likelihood, Kolten Wong will be back to making frustrating errors but making enough strong defensive stops and turning enough immaculate double plays to be very worth it in 2018. And as a complete package, while Wong will probably never be the guy in the Cardinals’ lineup, he can be a very solid contributor to a very good baseball team.