What happened: Kazuma Okamoto reached the milestone on September 8.
Why it matters: Ten previous seasons featured two rookies with 30 or more homers. [MLB](https://www.mlb.com/news/sal-stewart-munetaka-murakami-kazuma-okamoto-first-trio-of-rookies-to-hit-30-homers)
By the numbers: Sal Stewart: 31 home runs; Munetaka Murakami and Kazuma Okamoto: 30 each. Combined: 91. [MLB](https://www.mlb.com/news/kazuma-okamoto-hits-30th-homer-of-mlb-rookie-season)
What to watch: The rookie home run lead remains in play through the rest of the regular season.