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Twins rookies Alex Kirilloff and Trevor Larnach are showing they belong

John Foley

Alex Kirilloff (left), Trevor Larnach (right)Kirilloff: Brace Hemmelgarn / Minnesota Twins / Getty Images; Larnach: AP Photo/Tony Dejak

With the Minnesota Twins quickly running out of time to turn around a season that has seen their playoff prospects fade significantly, the focus for the organization will begin to shift away from contending now to preparing to contend in the future. In the increasingly likely event the Twins decision makers decide to turn the page on 2021, a great deal of attention will be paid to the upcoming July 30 trade deadline when many of the Twins’ veteran players will be made available to other teams in trade offers for young prospects that might be able to help the team in future seasons.

In addition to the trading deadline, the team will likely increase the playing time given to young players to give them a valuable development opportunity at the highest level. This will also give the Twins management an opportunity to evaluate them in the Major League environment.

A bright spot in that context is that the team is already getting a head start on evaluating two of their most highly regarded prospects. Thanks to a rash of injuries among Twins outfielders, corner outfielder/first baseman Alex Kirilloff (Minnesota’s #2 Prospect per MLB.com) and corner outfielder Trevor Larnach (#3 Prospect) are already nearly every day regulars in the Minnesota lineup. Not only are the two getting regular playing time, but through their first month or so of big league action, they are demonstrating that they belong.

Kirilloff, a 2016 first round pick out of a Pittsburgh area high school famously debuted during last season’s playoff series against Houston. This season, he served as the Twins’ 27th man for a doubleheader with Boston on April 14, giving him the rare distinction of being a player who took 7 MLB plate appearances before officially debuting on the Twins’ active roster. That debut would come on April 23. Now, Kirilloff has played in 30 games and split his time between the two corner outfield positions and first base. Altogether, through games played on June 9, he’s taken 117 plate appearances and provided a batting line (average / on base / slugging) of .255 / .291 / .436. By weighted on base average (wOBA), a comprehensive measure of offensive value, Kirilloff’s season long production checks in at .312, which is just a tick above the overall league average of .310. That is all the more impressive when you consider Kirilloff has also been playing through a nagging wrist injury that has limited his power and pulled down his overall numbers slightly.

Larnach had a more traditional major league debut. A first round pick out of college baseball powerhouse Oregon State in 2018, Larnach was summoned to the Twins from St. Paul when Byron Buxton went to the injured list on May 7. Splitting time between the two corner outfield positions, Larnach has now played in 27 games and accumulated 98 plate appearances through June 9. He’s batted to a .259 / .388 / .432 line that works out to a very strong .365 wOBA.
Given the similarity of their prospect pedigrees, positions, body types, and left handed swings, Kirilloff and Larnach will be paired together and compared to each other for the duration of their Twins’ tenure. It’s easy to assume they are the same kind of hitter, but that’s not quite accurate. Both possess plenty of power and project as middle of the order hitters, but their approaches at the plate deviate noticeably in terms of aggressiveness.
Kirilloff is the more aggressive of the two and he has swung at about 55% of the pitches thrown his way (for context, league average is about 47%). Larnach is more patient and has swung at about 44% of the pitches he has seen. Kirilloff’s aggressiveness leads him to chase pitches that are out of the strike zone more frequently and take fewer walks than Larnach. That point is evidenced by Kirilloff’s 32% chase rate and 5.1% walk rate compared to Larnach’s 26.7% and 13.3%, respectively. The league average chase and walk rates are 28.4% and 8.9%.
While 100 or so plate appearances is a small sample, this early data gives us insight into how Kirilloff and Larnach are going about their business. The swing and chase numbers do a lot to explain the difference in their on base percentage stats shown above and give a good indication of what we can likely expect from them going forward. In the long run, Kirilloff’s more expansive approach is likely to hit for a higher average, Larnach’s patience should lead him to run higher on base percentages, and both are expected to provide plenty of extra base hits.
Despite the differences in approach, both player’s underlying statistics should give Twins followers lots of confidence that these two are the real deal. Thanks to Statcast’s detailed measurements we can understand how well they are swinging the bat based on the quality of contact they make on batted balls, using data points like exit velocity, launch angle, hard hit rate, and barrel rate. In both cases, these stats are very impressive and compare very favorably to MLB averages:
Data sourced from baseballsavant.mlb.com

Using that data, MLB has developed a suite of “expected” statistics -- expected batting average, expected slugging percentage, expected weighted on base average -- that estimate a player’s numbers based on their contact data.

Here are those estimated numbers compared to actual for both Kirilloff and Larnach:

Data sourced from baseballsavant.mlb.com

In both cases, the quality of their contact more than supports their performance so far and, especially for Kirilloff, suggests they should have even better numbers.

As is often the case with rookie hitters who find success, opposing pitchers make adjustments to how they attack them. The primary way opponents are adjusting to Kirilloff and Larnach is by reducing how often they throw them fastballs. Kirilloff saw 47-48% fastballs in April and May. So far in June, that fraction has decreased to 34%. Larnach saw 51-52% fastballs in May and has seen only 40% fastballs in June.

In exchange, pitchers are offering them more breaking balls and offspeed pitches. Kirilloff was thrown 25% breaking balls in April, 37% in May, and now 45% so far in June. Larnach saw 24% of both breaking balls and offspeed pitches in May and those fractions have increased to 31% and 29%, respectively, so far in June.

There are good reasons for these adjustments. Both hitters have feasted on fastballs so far.

Kirilloff has hit .327, slugged .633, and delivered 9 of his 11 extra base hits off of fastballs. Against breaking balls, his average and slugging percentage are just .167 and all of his hits are singles.

For Larnach, the disparity is even more stark. He has batted .419, slugged .744, and produced all 8 of his extra base hits against fastballs. Against breaking balls and offspeed pitches, those numbers are .063 (both batting average and slugging) and .091 (both), respectively. More worrisome is that Larnach’s swing and miss rate (Whiff %) leaps from 19% against fastballs to 51% and 63% against breaking balls and offspeed pitches.

Both players are starting off from a wonderful place and finding early success. But, continued success is far from a guarantee. How well they adapt to the challenge of pitchers making adjustments in how they pitch them will dictate how successful they can be. For now, though, they've done nothing but show they belong.

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I analyze and write about the Minnesota Twins. My perspective has been developed from my lifelong fandom of the Twins, collegiate playing days as a pitcher, and graduate education in business and analytics. My goal is to use my experience in baseball and familiarity with its numbers and data to explain, inform, and educate about the events happening on and off the field.

Minneapolis, MN

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