Split Decision: A Breakdown of Pete Alonso’s 2021 Splits

Mike Kurland dives into Pete Alonso's splits from the 2021 baseball season and discusses the changes that occurred in the second half.

Every year players have interesting splits. Some start strong and some finish strong. Some have notable splits against left-handed pitchers or right-handed pitchers. This article will discuss one player with notable splits and discuss what changed in the profile to produce the change in numbers.

If a player makes drastic changes to an approach or profile it could lead to being more than a hot stretch. The goal is to identify some players who made these types of changes. This will be an ongoing series. Lastly, please note that this is meant to inform you on the numbers and changes in production that led to the changes in production. This should help you in creating your own opinion on a player as there will be no personal bias implemented within the breakdown.

Pete Alonso’s 2021 Splits

Pete Alonso has been great at various points in his young career. He continues to tease us with big seasons, hot runs and big second halves. 2021 was no exception. After a mediocre start, Alonso turned it on in the second half.

PABB%K%ISOBAOPSwOBAwRC+
3138.921.4.227.249.802.340118
3249.918.5.285.275.921.385147

Alonso went from very good to flat out great and was a four-category producer down the stretch. What did he change in his approach to accomplish these changes?

  • He lowered his average launch angle from 16.3 degrees to 13.1 degrees. He did so while maintaining an elite barrel rate in the process. Although you can see the change began in May.
  • The hard-hit rate improved slightly from 46.9% to 47.6% but it was a steady climb throughout the season also starting in May.
  • He sustained a good fly ball rate (40.4%) in the second half while improving the line drive rate to 20% from just 16.4% in the first half. This can help explain some of the BABIP and batting average gains.
  • Alonso pulled the ball more and the HR/FB rate jumped up as well from 17.5% to 22%.
  • The only red flag was the drop in zone contact. From 88.3% to 84.4% (still above league average) but he countered those losses with gains in O-Contact% from 61.5% to 66.1%. you would prefer the higher zone contact typically as it would typically lead to a better quality of contact but this approach as a whole still improved his numbers even if the plate discipline profile has some oddities.

Room For Improvement?

Pete Alonso does not struggle against LHP considering he has a career .886 OPS and a 132 wRC+ against them. However, he has just a .231 career batting average and strikes out 26.9% of the time against LHP. This is 33 points lower than what he hits against RHP (career .266 vs RHP) and a 3.6 point higher strikeout rate against LHP (22.3% career vs RHP).

This is absolutely nitpicking but as a right-handed hitter he could improve that batting average against LHP and it should not be a surprise if that occurs. Given the high floor of overall production, we are looking for the reason of optimism and reasoning he could continue to improve and this is where he could.

2022 Fantasy Baseball Outlook

Pete Alonso is currently the fifth first baseman off the board in NFBC leagues and he could finish as one of the top three without question. If all goes right for Alonso he could end up in that top tier at the position. He has elite power, elite barreling skills to back it up and continues to improve his plate discipline. In 2021 Alonso had a career-low SwStr% of 11.4% (which has improved two-straight seasons) while having his career-best contact rate of 76.5%. He has done this while becoming more aggressive at the plate and it has assisted in the gains in batting average as well as decreasing the strikeouts. He continues to improve his game each year and although 2019 will be tough to fully repeat we cannot count him out if these trends in production continue.


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