One of the most notable free agent signings last season was when the Houston Astros signed Christian Walker to be their starting first baseman for the foreseeable future with a 3-year, $60M contract. Nearly two years after signing José Abreu to a similar contract which did not end in the way Houston intended, the Astros entered with the expectation that Walker’s track record of offensive production and above-average defense would provide stability at the position over the next three seasons.
Over his first 167 plate appearances with the Astros, however, Walker has struggled offensively, on pace to produce his lowest wRC+ and fWAR since the 2021 season. This article will take a closer look at Walker’s offensive profile, identify the roots of his offensive struggles this season, and assess whether Walker’s early-season struggles are a temporary blip or foretelling signs of long-term decline.
Overview
Over the past three seasons, Christian Walker has been one of the best first basemen in all of Major League Baseball. Initially becoming Arizona’s first baseman after the trade of Paul Goldschmidt before the 2019 season, Walker produced a wRC+ of approximately 120 and an ISO greater than .200 in each of the past three seasons. Combined with being among the league leaders in advanced metrics, such as fielding run value, Walker was one of the more intriguing players available for acquisition this past offseason.
As shown by the table above, Walker is currently slashing .213/.287/.353, producing an 84 wRC+ with a 7.2% walk rate and 28.7% strikeout rate over his first 167 plate appearances of the season. The offensive output that Walker has shown early this season, with declines in wRC+, ISO, strikeout rate, and walk rate, have raised concerns about the level of offensive production that Walker will be able to produce moving forward.
As I discussed in my article about Pete Alonso last week, the minimum offensive bar that a first baseman needs to clear to generate positive overall production is high, and any significant decline in offensive production threatens to derail Walker’s profile as a whole if he is not able to reclaim his prior levels of offensive production.
To identify the areas of his offensive approach that Walker needs to improve upon to reclaim his prior levels of offensive production, I displayed Walker’s Process+ metrics in the table above. Walker has always displayed below-average Contact ability according to these metrics, which is backed up by his greater than 11% swinging strike rate in each of the past three seasons.
The two areas in which Walker has experienced a decline this season compared to his 2024 levels have been his Decision and Power ability. Walker has consistently displayed above-average Decision ability, which has declined from 112 to 101 so far this season, while Walker’s Power ability has declined to his 2023 level according to the model. This decline in Power+ from 115 to 102 suggests that while he still retains above-average Power ability, Walker might be approaching the other side of the aging curve, and given the accompanying decline in bat speed and batted ball quality, there is a high probability that Walker’s power output should be revised downward moving forward.
Power Ability
After posting an ISO above .200 in each of the past three seasons, Walker’s current ISO of .143 represents a sharp departure from the power production he has displayed in recent seasons. This decline in power production has been a major driver behind Walker’s decline in offensive production in 2024 and threatens to negatively impact his long-term outlook if it does not positively regress in the near future.
As shown by the table above, Walker has experienced a decline in nearly every batted ball metric this season compared to 2024, as his barrel rate has declined from 13.3% to 9.7%, his hard hit rate has declined from 48.0% to 45.6%, and EV50 has declined from 103.1 to 101.9.
Could Walker simply be regressing to his 2023 levels of power production? It is possible, given that Walker produced a 99 Power+, 100.6 EV50, and 40.4% hard hit rate in 2023 (all lower values than what he has produced so far in 2025), however, Walker’s decline in bat speed has raised the most eyebrows regarding a potential decline in “true talent” offensive output.
During the second half of the 2023 season and the 2024 season (where Statcast bat tracking data is publicly available), Walker displayed an average bat speed of 75.0 MPH. So far in 2025, Walker has been displaying an average bat speed of 73.7 MPH, a 1.3 MPH decline from last season. Bat speed data becomes reliable for hitters very quickly, with a sample size of fewer than 10 swings, indicating that this decline in bat speed is very likely a sign that Walker is on the opposite side of the aging curve. Walker turned 34 in March, and bat speed typically begins to decline after a player’s age-31 season.
This decline in bat speed places more pressure on Walker’s ability to “square up” the baseball to generate high exit velocities on batted balls, and since Walker has consistently shown a below-average ability to square up the baseball, this decline in bat speed does not bode well for his long-term power outlook. For these reasons, it appears that training for bat speed after the conclusion of this season will be a likely course of action for Walker to take to “stave off” this regression in batted ball quality and provide positive value to Houston throughout the remainder of his contract.
Decision Ability
In addition to the decline in power production, another key area of regression in Walker’s offensive profile has been his decision-making at the plate. After posting above-average Decision+ scores in both 2023 and 2024, Walker has seen this number decline to 101 in 2025. This decline in swing decision ability can be largely attributed to his chase rate, which has increased by over 6% from last season.
As shown by the table above, Walker has been swinging at pitches outside the zone more frequently this season, which has led to his decline in walk rate from 10.0% to 7.2%. In addition, Walker has been swinging at pitches inside the zone less frequently which, when combined with his increased propensity to chase, has led to a regression in his ability to be selectively aggressive at the plate and providing himself fewer opportunities to swing at pitches that he can drive for power.
The driving force behind Walker’s decline in swing decision ability has been his tendency to swing at sliders and sweepers located out of the zone so far this season. As shown by the table above, Walker has experienced a 13.1% increase in chase rate against sliders to start the season, contributing to a 10.1% increase in whiff rate against these pitches. Opposing pitchers have taken notice that Walker is struggling against these pitches this season, increasing their usage rate of sliders from 24.6% to 25.3%, however, Walker is still producing hard contact when making contact against these offerings (57.9% hard hit vs. sliders, 58.3% hard hit vs. sweepers).
The driving force behind Walker’s increased susceptibility against sliders and sweepers is a bit of a mystery according to data that is publicly available, and the potential reasons for this sudden decline could range from he’s having trouble tracking these pitches in his new home ballpark to he’s “opening up” his swing too early, leaving him more vulnerable than before to swing-and-miss on the outer-third of the plate. Regardless of the root cause, it appears likely that Walker will face an increasing number of sliders and sweepers throughout the remainder of the season as long as this newfound chase tendency persists, especially against pitchers who have a good feel for their sliders and have confidence that they can locate the pitch in an area where Walker will frequently chase. Combined with the regression in power output, this decline in swing decision ability has lowered Walker’s offensive floor and raises questions about his long-term offensive outlook.
Concluding Thoughts
While this article has spent a considerable amount of time taking note of the flaws in Walker’s current offensive approach, there are some bright spots that he’s displayed early in the season that provide optimism that he can turn his season around and reclaim his prior levels of offensive approach. First, Walker still pulls the ball in the air at a high rate, with his current 22.5% pull air ranking as the highest of his career. Pulling the ball in the air is a valuable batted ball outcome as, for a multitude of reasons, these batted balls produce the greatest results by measure of wOBAcon. This skill is especially important at a park with such a short left field fence, such as the one at Daikin Park, and provides optimism that Walker can continue to generate plus power production (even at lower exit velocities) by hitting balls into the Crawford Boxes.
Second, projection systems are still optimistic that Walker will be able to bounce back this season, with THE BAT X projecting Walker with a 119 wRC+ and OOPSY with a 113 wRC+ over the remainder of the season. If Walker were able to reach these projections, it would result in him accumulating ~2 fWAR over the course of the season which, if using a simple $10M/WAR assumption, would result in Walker meeting the value he was expected to generate per the terms of his contract ($20M AAV, ~2 fWAR per year). Third, hitters typically gradually improve their plate discipline as they become more familiar with Major League pitching and the strike zone relative to their peers, providing some optimism that Walker’s increase in chase rate could be a temporary aberration. On the other hand, frequently cited aging curve research conducted by Bill Petti shows that hitters tend to increase their swing rates after age 33, and Walker is currently in his age 34 season.
Last week, I discussed Pete Alonso’s free agency and the potential downsides that can occur with signing a free-agent first baseman who is over the age of 30. While Alonso has displayed to his skeptics that he “should’ve” been awarded a larger contract over the offseason, Walker has displayed the lack of production value (by measure of WAR) that a first baseman provides when their offensive production declines. Unlike Alonso, Walker is a top-tier defensive first baseman which provides him with a small cushion of production to fall back on if the bat permanently regresses. With nearly two and a half seasons remaining on his contract, the Astros are betting that Walker’s track record and top-tier glove will carry him through this early-season slump, however, it is imperative that Walker improves his level of offensive production to maximize the amount of value he can provide to the Houston Astros moving forward.
Statistics through the end of play on May 13th, 2025.
Photo by Joe Robbins/Icon Sportswire | Featured Image by Justin Redler (@reldernitsuj on Bsky/Twitter)
