Tuesday’s series opener with the Cincinnati Reds became a showcase of four-seam fastballs.

Alec Mills threw a season-high 48 four-seamers, obliterating his prior game high of 21. Tyler Mahle followed suit by throwing 58 of his own, also a season high for the Reds’ right-hander. But Mills left the battle victorious as the Cubs shutout the Reds 3-0 thanks to his clean start.

It wasn’t just the amount of four-seamers Mills threw, but how he mixed it in with his sinker and how well he established it early. Through the 3rd inning, Mills had thrown 83% four-seamers and sinkers, nearly 25% above his average usage of those two pitches combined this season entering Tuesday (53%). His reliance on fastballs seemed to be part of a broader plan to mix up his attack against a team he faced for the third time this season and sixth time dating back to 2019.

“Little changes here and there can do big things,” Mills said after Tuesday’s start. “Different fastballs, different parts of the zone up and down, especially to lefties.”

Once Mills established his fastball, it opened up the rest of his repertoire and allowed him to avoid duplicating pitches and sequences when facing hitters for the third time.

When Mills faced the left-handed Shogo Akiyama in the 6th inning, instead of opting for fastballs, he threw two curveballs and a slider. Later in the 6th, he squared off against Nick Castellanos and threw three consecutive sliders to bury the Reds’ leading home run hitter. Castellanos whiffed at all three off the plate and Mills escaped one of the few jams he found himself in Tuesday.

“My slider is a pitch that I haven’t been throwing a lot recently but it can generate a lot of outs,” Mills said.

Mills’ 12 sliders tonight did not eclipse his season high of 21, but the five whiffs he generated did. The depth of his repertoire, even if there is a strong reliance on two kinds of bread-and-butter fastballs, allows Mills to stymie a lineup after seeing them what seems like every other outing. 

“[Mills] established his fastballs early just like Kyle Hendricks did in [Monday’s] game,” Marquee Sports Network analyst Sean Marshall said. “Because everything comes off of fastball command.”

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