One of the biggest mysteries of the 2022 season is Christian Walker’s batting average on balls in play (BABIP). Walker has made improved contact this season, ranking 12th amongst MLB hitters in barrel rate per plate appearance, but it hasn’t translated too much into his bottom line results. On the season, Walker is putting up a power-driven .208/.304/.490 triple slash which still puts his overall offensive production at 22% above the average hitter according to OPS+. While his offensive production is still more than satisfactory, with his overall value estimated to be 1.6/2.4 wins above the replacement first baseman, you feel like there should be more to the table in terms of his hitting.
Earlier in the year, I pointed out how Walker’s Statcast expected stats seem to indicate that he’s having a breakout year. That is still very much true, but it’s a weird breakout year in which the power and defense have broken out but the average hasn’t followed. One of the key factors driving down Walker’s numbers is a .187 BABIP. That’s a number that is unsustainable over the course of the season, based on historical precedent. In the Division Era (1969-present), there have been 20 instances of a player having 500 plate appearances and a BABIP under .250. The lowest BABIP in that group is when Albert Pujols had a .217 BABIP in the 2015 season. Of this group, the lowest home run count is 39 and the lowest OPS+ is 107. Walker is on pace for just under 40 home runs this season and his OPS+ of 117 would be far from the lowest in that group.
Another metric that also clouds the picture is Statcast’s expected batting average (xBA) stat. xBA suggests that Walker’s quality of contact should result in a .277 batting average, 69 points higher than his actual average. When there is such a big discrepancy, then we need to take a deeper dive into the type of contact he’s making and if there are any underlying factors behind that discrepancy.
What type of contact is Walker making?
Before we break down areas that have the most impact on Walker’s BABIP, we need to take a look at the type of contact Walker is making. Walker’s average exit velocity has jumped nearly 2 MPH compared to last season, back up to 90.5 MPH. The biggest noticeable change is a jump in launch angle from 15.6° last season to 18.2° in 2022. That has resulted in Walker’s ground ball rate dropping while seeing an increase in fly ball contact. The combination of an increase in exit velocity and launch angle typically suggests a power breakout, which is true as Walker is on pace to shatter his previous career-high in both home runs and isolated slugging% this year.
Walker’s big fly ball jump has also come at the expense of line drives. In 2022 so far, hitters are batting .627 on line drives and a BABIP of .614. Walker’s line drive rate has dropped from his career average of 25% down to 17%. That trade-off has been the biggest change in his batted ball profile compared to last year, so that has the largest impact on Walker’s BABIP. Another noticeable change is Walker is pulling a lot of pitches, putting up a career-high pull rate of 41.4%. That can be a double-edged sword, as fly ball and line drive contact becomes more valuable but ground ball contact becomes less valuable at the same time.
Walker is getting shifted more and is hitting right into it
The biggest difference between this season and previous seasons is Walker is drawing more shifts, whether they’re classified as strategic positioning or a shift according to Statcast. I classified both as a shift, since they’re both a case of the opposing team realigning their infield beyond what is considered typical. Here’s how often Walker has seen a strategic or positional shift in the opposing team’s infield alignment.
Whether it’s a case of recent batted ball trends or just teams deciding to be more aggressive with shifts, you can see Walker is getting infield shifts much more frequently than in year’s past. By itself that’s a metric not to be too worried about, but it’s compounded by the fact that Walker plays right into the defense’s hands. Walker has only hit 5 ground balls classified as opposite field according to Statcast. The league average on ground balls that are either pulled or hit straightaway against a defense in either a strategic or shift alignment is .188, and that mark drops to .145 against similar defenses when isolating for only pulled ground balls.
Accounting for Walker’s ground ball metrics and the league numbers of these type of ground balls, there is staying power behind his .136 batting average on ground balls. His average may make a small improvement between now and the end of the year, but unless he starts hitting ground balls away from shifted infielders his ground ball average will not improve much. Ground balls account for 36.3% of the balls that Walker has put into play, so that has a big impact on why that number is low.
Is Walker selling out for power?
When we look at the high pull rate for Walker, which is a career-high rate of 41.2%, we ask if he’s selling out for power. His strikeout and walk rates are better than his career averages, and he’s not chasing out of the zone either. Walker’s chase rate of 22.4% ranks in the 83rd percentile for hitters. One area where Walker rates below average is whiff rate, or swings that completely miss the ball, which is in the 40th percentile with 26.5% of his swings coming up empty. Putting all those together, we can rule out that he’s disregarding plate discipline to try to get more power.
One other area we can look at is Walker’s fly ball rate. Walker’s fly ball rate, without accounting for pop flies, has jumped to 38.4%. That fly ball rate is easily the highest of his career, being more than 15% above his career average of 22.9%. Of those fly balls, Walker has a BABIP of .130, which is close to the league average of .125. Of the 73 fly balls that Walker has hit this year, 26 of them are pulled (35.6%). That’s 9% higher than the league average of 26.4% fly balls that are pulled and Walker’s reaping the benefits although it’s not affecting his BABIP. Despite a BABIP of .000 on that type of contact, Walker is hitting .560 with 14 homers on pulled fly balls. That makes sense, as Walker has an average fly ball/line drive exit velocity of 94.5 MPH.
Based on Walker’s big jump in fly ball rate and overall pull rate, we can assume he is selling out a bit to get more power. It’s been a mixed bag, as Walker is on pace for career bests in park-adjusted offensive metrics like wRC+ and OPS+, but has seen his average crater to .204 on the year.
What is Walker’s true BABIP skill?
Knowing that Walker is making the type of contact that’s less conducive to a higher BABIP, the question we ask is what his BABIP should be? As mentioned above, the Statcast expected stats are a big reason why there’s a confusion between Walker’s expected performance vs. actual performance.
The first place to look in order to find a predictive BABIP formula is Fangraphs. Mike Podherzer has tinkered around with an xBABIP based on different hitter outcomes, although recently has added a new formula for the 2020 seasons and beyond. You can check out all the research he did, but I won’t bore you with the details here. The formula uses a xBABIP from Statcast numbers with hits being replaced by xBA*ABs, then severely penalizes hitters to pulling ground balls into a shifted infield defense and rewards hitting opposite field ground balls. Using Walker’s xBA of .277 from Statcast, I calculated an expected BABIP of .286 based off Statcast data. Walker has pulled 14 ground balls into a shifted infield defense, which gives us a rate of 8.19% of the balls he puts into play resulting in that type of contact. He’s hit just 5 opposite field ground balls all season long, or 2.92%. Plugging in all three of those values into Podherzer’s equation alongside an average Sprint Speed of 26.9, the formula spits out an xBABIP of .275 for Walker.
I have some reservations about using xBA stat from the 2022 season, as the league batting average has underperformed it’s expected batting average by 13 points. That is the largest gap between the two in the entire Statcast era, surpassing the 9 point difference from the first year it was implemented in 2015. The easy argument to write it off is teams have played around 70 games this season and the sample size is too small to make a definitive argument. That argument is easily disproved because of the zero point difference between the league batting average and expected batting average in the 2020 season, which played fewer games in their regular season. If you are curious to see how BA and xBA have compared to each other during the Statcast Era, here is a table of those two stats sincew 2015.
League BA and xBA in Statcast Era
|Year||Lg BA||Lg xBA||Difference|
|Year||Lg BA||Lg xBA||Difference|
Since there is such a huge difference between actual and expected batting average, I decided to take that 13 point difference and apply it to Walker’s xBA. With that .264 xBA as the input instead of .277, Podherzer’s xBABIP equation yields an xBABIP of .258 for Walker. Compared to how he’s looked over 70 games, his true BABIP skill is likely closer to the .258 figure than .275.
Based on historical precedent, we can easily assume that Walker’s .187 BABIP in 2022 is very unsustainable. The lowest single-season BABIP in the past 50 years is Albert Pujols’ .217 mark from the 2015 season, which is 30 points higher than Walker’s current value. Walker is likely selling out a bit to get more power to stay in the majors after a difficult 2021 season, which has caused his numbers to closely resemble low average, high ISO sluggers like Dave Kingman. Walker is pulling more pitches than ever before, which has made him more vulnerable to infield pull shifts where a ground ball to the 3rd base side of 2nd is an automatic out. At the same time all of his pull-side fly ball hits have left the ballpark, with Walker hitting 13 home runs from that specific batted ball demographic.
For the 2022 season, we can also assume that Statcast’s expected stats are also messed up to the point where they’re unusable. Beyond just the 13 point difference in batting averages, slugging has underperformed expected slugging by 45 points and wOBA has underperformed xwOBA by 19 points. For as to why this appears to be the case, we can assume it has to do with the league mandating all 30 ballparks use a humidor to store baseballs before game as well as continued issues with manufacturing baseballs ever since they took that process over from Rawlings in 2017.
Looking at the quality of contact and the limitations of Statcast metrics this season, I believe Walker’s true BABIP skill lies in the .250-.260 range. If he can maintain that rate over the second half the season, his season BABIP will likely finish in the .220-.230 range. I think we can expect him to finish around an average right around .225-.230 and roughly 40 home runs with league average baserunning values and Gold Glove caliber defense at first base for 2022. That total package likely finishes somewhere between 3.0-4.0 WAR, which is something you’ll take at any position in absence of future upgrades.