Matt Carpenter is swinging and missing more in 2015

The leadoff hitter, err, two-hole hitter of the St. Louis Cardinals started his 2015 campaign by significantly outpacing his 2013 MVP-candidate numbers. From opening day 2015 through May 6th (27 games played), Matt Carpenter slashed .333/.403/.620, as compared to a .288/.351/.471 slash line in 2013. Then, on May 8th, it was reported that Carpenter would not be making the weekend trip to Pittsburgh as he was dealing with a health episode classified as "extreme fatigue," in which he was prescribed rest.

After a slew of medical tests uncovered no serious underlying condition behind his fatigue symptoms, Carpenter rejoined his teammates in Cleveland on May 12th, admitted that he probably should not argue with Matheny about days off anymore, and has since received one game off (plus two days off along with June 14th's postponement) in the process.

Putting it bluntly, it is simply unfair to have expected Carpenter to maintain his early-season pace throughout 2015. He was a prime candidate for regression. However, we have seen an uncharacteristic drop in performance at the plate since his return to the starting lineup against the Indians, with his power being sapped and a sagging slash line of .260/.361/.382. An on-base percentage of .361 is still more than respectable, but that slugging percentage is nearly 60 points lower than his career average of .441. His batting average, while not the most valuable statistic when evaluating a hitter, has been 30+ points below his career norm as well.

So what is to blame? A change in personal approach? Being attacked differently by pitchers? Lasting fatigue? Bad luck? A combination of all four? Unfortunately, I do not have a concrete answer for this question. If I did, it is likely Carpenter, the coaching staff, and, if needed, the medical staff would have already figured it out themselves. Yet, it does not hurt to ponder the situation.

Regarding personal approach, Matt Holliday provided his opinion on Carpenter to Derrick Goold back in February:

"It’s great to walk and have long at-bats but he’s got the potential to hit 50 doubles. We’ve seen it. He’s got the potential to hit 15 to 20 homers. We saw that in the postseason. It’s fine that first at-bat of the game if you want to take some pitches. But I’d like to see him be a little bit more aggressive. It’s in there. He showed it. It’s in there for all of us."

So far in 2015, Carpenter is 11th in baseball with 4.19 pitches per plate appearance, down from 4.37 (3rd) in 2014, but up from 4.12 (19th) in 2013. Thus, while Carpenter may be more aggressive than he was last season, he has actually been less aggressive than he was during his breakout 2013 season. Regarding pitchers attacking him differently, this is a tough to discuss briefly and would require its own post entirely, but a quick glance at 2015's zone profile shows that pitch location has been very similar to what it was in both 2013 and 2014. That leaves fatigue. Given that Carpenter has only been given one game off since returning from his three-game hiatus, on the surface, this does not appear to be the issue, either.

While I have already surrendered the possibility of making a concrete inference as to what is going on, I can describe a component of Carpenter's performance that is unquestionably different this season. He is swinging and missing (aka "whiffing") more frequently than he has in the past.

Swinging strikes through June 17th of each respective year:

via BaseballSavant.com

Of note, plate appearances for Carpenter through June 17th were 302, 320, and 264 for 2013, 2014, and 2015, respectively. Thus, while not exactly equal due to Carpenter's bout with fatigue plus moving down one spot in the lineup, 2015's smaller sample further highlights the disparity we have seen thus far this season. Through June 17th in 2013 and 2014, Carpenter had 41 swinging strikes. Thus far in 2015, Carpenter has had 64, a 56% increase from the previous two seasons. My first thought, prior to pulling up these graphs, was that Carpenter was expanding his zone, largely because of the constant battle he is forced to endure with home plate umpires' strike zones. As you will see below, this does not appear to be the case, though:

Called strikes through June 17th of each respective season:

via BaseballSavant.com

On a rate basis (useful since we are dealing with unequal sample sizes), there has indeed been a slight uptick of called strikes on pitches out of the zone in 2015 (as compared to 2014), with down and inside being the main culprit (never forget). Yet, despite umpires' expansion of the "strike zone" inside and off the plate, Carpenter does not appear to be swinging and missing at these pitches any more frequently than he has in the past.

Instead, what is particularly worrisome is the fact that Carpenter is swinging and missing at pitches in the strike zone more often than he ever has. Again, through June 17th, the third baseman has swung and missed at 27 pitches in the strike zone, as compared to nine in 2013 and 10 in 2014. Five of these 2015 whiffs have taken place on pitches right down the middle of the plate (a zone in which he has posted .389 career batting average). Six more have occurred in the zone Carpenter reserves for driving balls into the left-center field gap for his patented doubles.

Here is to hoping that Carpenter is just experiencing a miniature blip in his performance and that he will soon return to his normal self regarding swinging and missing. If you have a theory as to what is going on, please share it below.

Credit to BaseballSavant.com for the graphs used in this post.