Marcus Semien’s Swing Has Clicked in September

I remember the first time I heard Marcus Semien talk about hitting. Coming off a fantastic season with the Blue Jays, he was a finalist for the AL MVP award along with teammate Vladimir Guerrero Jr. and the eventual winner, Shohei Ohtani. Not many likely paid him much attention during his interviews on MLB Network’s award show; as you would expect, everybody was patiently waiting for Ohtani to talk about his historic season on a national stage. But in every Semien soundbite during his interview with Greg Amsinger, there was a fascinating tidbit about hitting and progressing through a season. Since then, I have looked at his at-bats differently.
That’s what made watching Semien in the first two months of the season mind-boggling. He was one of the worst hitters in baseball, with a 55 wRC+, and couldn’t keep the ball off the ground. I’m a big fan and supporter of his swing, but that performance had me doubting what his future would be. But the Rangers’ second baseman got hot in the early summer, posting a 137 wRC+ over June and July, and after an average August, his September has been one of the best months of his career, with a .337/.388/.589 line and a 177 wRC+.
Through all that, Semien’s hard-hit rate stayed consistent, including his awful start and two great months in June and July, but since hard-hit rate is strictly a measurement of exit velocity, that isn’t all that surprising. What is a shocker is how he’s nearly doubled that same rate month over month.
Month | Hard% |
---|---|
Mar/Apr | 23.9% |
May | 27.0% |
Jun | 25.3% |
Jul | 30.3% |
Aug | 24.5% |
Sept/Oct | 45.8% |
On the year, Semien ranks 95th in all of baseball in hard-hit rate, but in September, he has ascended to 15th among all qualified hitters. That type of jump is sticky and often indicative of a concrete swing adjustment. In other words, you don’t luck yourself into hitting rockets for this long. So let’s find out what that change was. Read the rest of this entry »