AnalysisNL Central

The Rise of Baby Hendricks

How Alec Mills has found success, and how he might be able to improve even further as a vital asset to the Cubs.

It’s the nature of no-hitters that they sometimes come from very improbable pitchers, and Alec Mills certainly proved that by blanking the Milwaukee Brewers for the 16th no-hitter in Cubs history on Sunday. Mills has been a vital component of a Cubs pitching staff that has run remarkably thin despite the lack of lethal arsenal such as that which his rotation mate, Yu Darvish, wields. His success is far more reminiscent of Kyle Hendricks, another member of the Cubs rotation who has become renowned for his ability to find success without throwing hard. Newly acquired Cubs outfielder Cameron Maybin dubbed Hendricks “Baby Maddux,” and a recent article by Patrick Mooney of The Athletic notes how Mills was acquired with his potential to develop into a Hendricks-esque starter in mind. Now, with the ability to work with and watch Hendricks, Mills (or “Baby Hendricks”) is finding major league success of his own in a similar manner, and his continued performance will be crucial to the Cubs moving forward.

Mills was originally acquired by the Cubs prior to the 2017 season in one of the multiple trades with the Royals that preceded that year. Mills had cracked the majors with Kansas City in 2016, but was still not quite a finished product and missed most of 2017 due to injury, and in 2018 still had a 4.84 ERA in 124 innings in Triple-A. Even in 2019, Mills spent most of the season in Triple-A and had an even higher ERA at 5.11, but he was in the midst of making an important change: slowing down his curveball, an adjustment that paid dividends when he did pitch with Chicago in 2019 as well as thus far this season. According to the article linked above from Jordan Bastian of MLB.com, Mills had the slowest average curveball speed of any pitcher with at least 50 curveballs in 2019.

According to Baseball Savant, Mills’ arsenal in 2020 includes five pitches: the aforementioned curveball, a four-seam fastball, a two-seam fastball (or sinker), a changeup, and a slider.

Alec Mills’s 2020 pitch distribution. Both his sinker and four seam fastball are grouped together under “Fastball,” though they’re typically about the same speed. The leftmost number beside each pitch shows the percentage of the time that Mills throws that pitch.

One thing generally jumps out from this graph: Mills’s pitches are slow. The vertical dashed lines are the MLB average speed for each pitch type, and Mills hasn’t thrown a single pitch that even reaches the average speed for any of the pitches he throws. Remarkably slow is his curveball, which averages even slower than in 2019 at 66 MPH and is barely even on this chart. In a baseball world where pitchers grab attention by lighting up radar guns (the Cubs own fourth round draft pick this year, Luke Little, only made it on draft boards at all because he touched 105 MPH in a bullpen session), Mills is barely even powering the radar gun at all.

In fact, spin rate has become an increasingly important focus for pitchers as well, and Mills doesn’t excel in that department either. This means that Mills can’t induce swinging strikes like some of baseball’s more dominant pitchers, and has pretty low strikeout totals as a result.

That only leaves one aspect of the game for Mills to find success: limiting quality contact. One look at his percentile rankings among MLB pitchers tells you that, in general, he does exactly that:

Alec Mills’s percentile ranks among MLB pitchers. Note: due to the desire to maintain a system where higher percentiles equate to better performance, exit velocity, hard hit percentage and barrel percentage are ranked inversely. Example: a pitcher who yields a higher average exit velocity will rank in the lower percentiles of exit velocity on this chart. Thus, Mills allows a lower average exit velocity than his hard hit% and barrel% would suggest.

That’s a pretty remarkable distribution to find any success with whatsoever. Mills is in the bottom 40 percent of every component of pitching except limiting contact, and even then he is in the bottom half of everything except average exit velocity. Such a gap between average exit velocity and hard-hit/barrel% suggests that Mills allows his fair share of well-hit balls (AKA barrels), raising the hard-hit rate and barrel rate of hitters facing him. However, outside of that contact, he limits hitters to weak or medium contact that is more easily converted to outs. This is confirmed by batted ball data from FanGraphs, which indicates that Mills is around 15th to 20th among qualified starting pitchers in lowest average exit velocity as well as highest soft contact rate allowed, but simultaneously has a relatively high barrel percentage (18th) and average launch angle (23rd).

Ultimately, Mills has had his fair share of good luck this season as well. Opposing hitters have just a .211 batting average on balls in play (BABIP) against Mills, the second lowest mark of any qualified starter in baseball. He’s certainly due for some regression there, but not a ton given that he limits hard contact fairly well. For comparison, Trevor Bauer has the fourth lowest BABIP allowed among starting pitchers (.219), and contact off Bauer is 2.8 MPH faster on average than contact off Mills. Still, Mills can only get so lucky with hitters that do make contact off of him, and the difference between this year’s .211 BABIP and his career average of .247 is great enough to conclude that Mills has been rather lucky this year.

In fact, most of Mills’s results this year suggest some regression from his performance last season, with the caveat that both seasons were pretty small samples from which to draw any meaningful conclusions. Still, Mills’s 17.5% strikeout rate this year is lower than almost any season in his career, including in the minor leagues. A look at his pitch distribution by season helps identify where a difference may have began:

How frequently Alec Mills has thrown each of his five pitches by season. In 2020 he has significantly increased the usage of his sinker.

Mills has significantly increased the use of his sinker (two seam fastball), shown in orange, this season at the expense of his four seamer, also accompanied by a slight decrease in the use of his changeup and slider. One look at the GB% and xWOBA of opposing hitters on each of his pitches helps explain why:

Alec Mills’s xwOBA allowed by pitch

Throughout his major league career Mills’s four seamer has been his pitch against which hitters perform best, and this year is no exception. Mills has also likely switched in favor of the sinker because it’s a better ground ball pitch. Still, it’s fairly obvious from the graph that neither of Mills’s fastballs are his best pitch; in fact, they’re not even close. All three of his other pitches have lower xwOBA values than his two fastballs, and swing and miss as well as hard hit data helps explain why.

Percentage of swings that miss each of Alec Mills’s pitches.

Both of Mills’s fastballs are both his worst swing and miss pitches and his pitches that get hit the hardest. While his tendency to throw them more frequently suggests that they are important because he’s comfortable with them, Mills’s fastballs – especially his four-seamers – are his worst pitches for getting swinging strikes and the pitches that have the most potential to get hit hard in his arsenal. While Mills currently works with his fastballs as important setup pitches for his breaking balls, altering how frequently he uses some of his pitches may be beneficial in order to help him miss bats more frequently and lower the quality of contact he allows. One important note is that when Mills falls behind in the count he turns almost exclusively to his fastballs, throwing either his four-seamer or his sinker 100% of the time when he reaches a 3-0 count and over 50% of the time in every single count that isn’t 0-2 or 1-2:

Distributions of how frequently Alec Mills throws each pitch in each potential ball-strike count of a plate appearance. Counts further towards the right of the graph are considered “hitter’s counts” (the hitter has gained the advantage in that plate appearance) while counts further towards the left are considered “pitcher’s counts.” Mills leans heavily on his fastballs in any count except the most extreme pitcher’s counts.

Ultimately, Mills would benefit from simply attacking the strike zone more. His 45.6% of pitches thrown in the strike zone, below the MLB average of 49.9%, is low for a pitcher who does not have elite swing and miss stuff to get strikes from swings and misses outside of the zone. This leads Mills to fall behind in the count fairly frequently, and this is when he leans on his pitches that get hit the most. Mills does hit the edge of the zone at a rate (43.9%) that’s higher than MLB average (39%), but ultimately is still not getting strikes from these pitches at a rate that compensates. It’s difficult to say whether further experience in the major leagues will help Mills get more comfortable and allow him to be more aggressive with his best pitches, but it certainly won’t hurt.


These data points all suggest a conclusion that feels about right given Mills’s actual results so far: he’s an unorthodox pitcher who gets average results in a fairly unique way. He doesn’t throw hard, he doesn’t rack up strikeouts, he doesn’t even command the zone terribly well, but so far he has gotten outs, and boy has he been valuable in that regard for the Cubs. He may never quite become the second coming of Kyle Hendricks, but Baby Hendricks sure has been a bright spot for the Cubs this season with the absence of Tyler Chatwood and Jose Quintana, and he’ll continue to be a key piece of the team’s pitching puzzle even if he slides to the bullpen upon their return.

Mills has found a formula that yields major league results, and underlying data suggests he may still have better days ahead of him if he can maximize the potential of his pitch mix like Hendricks has. No matter what, Mills has been an asset for the Cubs this year, and with five more years of team control remaining, even pitching at a league-average level Mills will be an underrated asset for the Cubs for years to come.

Ryan Ruhde

Cubs, Royals and general analysis writer. Emory University Psychology/Music Performance Major and Pre-Med, class of 2023. Find me on Twitter @ruhdolph

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