Breaking down Gennett's 4-HR night pitch by pitch

As far as single-game feats go, Scooter Gennett's four-home run game Tuesday evening against the St. Louis Cardinals is among the greatest of all time.

Aside from hitting four balls into the seats, he also went 5-for-5, had 10 RBIs, and contributed nearly 28 percent of the Cincinnati Reds' win probability.

During Gennett's fifth plate appearance of the night - the one that would land him on a list that includes Josh Hamilton, Carlos Delgado, Willie Mays, and Lou Gehrig - some baseball fans couldn't help but think: "How on earth is this happening?"

That isn't meant to slight Gennett, who is, after all, gainfully employed at the highest level of his sport. But it's difficult to ignore the fact that the 27-year-old was posting a pretty average .141 ISO prior to this season. While that isn't especially low, it puts him between Alejandro De Aza and Desmond Jennings - two players not known for their slugging who are currently not in the major leagues - over the same time frame.

Related: Why Gennett's unlikely performance may have been the best of all time

So, how did this happen?

Omitting the current season, Gennett's zone profile indicates he generates most of his isolated power from inside pitches, both belt-high and low. Truthfully, though, he does well against anything in the heart of the zone or nearer to him - even down and in outside of the zone.

Our analysis must begin, though, with a tame single.

Gennett began his night by coming up to the plate with two runners on and two out in the first inning. He cashed in the speedy Billy Hamilton for his first RBI of the game following this swing:

You can see it in their immediate body language. Adam Wainwright is thinking "easy pop," and Gennett has a missed-that-one face. But no. On this night, the ball would have just enough hang time to fall safely between the shortstop and left fielder.

This is despite the pitch entering the strike zone right in Gennett's wheelhouse, too:

In all likelihood, the Reds outfielder saw fastball out of Wainwright's hand, but got fooled on the changeup.

The next time Gennett would come up to bat, though - with the bases full of Reds - he would get the inside fastball he was looking for, but just a couple inches lower. The result was as majestic and without doubt as home runs come:

By Gennett's next plate appearance, Wainwright had just left the game, giving up a single, double, and triple to start the fourth inning. John Gant was called on to address the problem that was Scooter.

Whoops. I guess it's hard to warn an incoming reliever not to throw that there if you're an upset starting pitcher who just wants to get in the dugout. This one went dead center to set up a home run every bit as majestic as the first.

This is the point in the game at which anything that came into contact with Gennett's bat started leaving the field of play.

The exchange between Gant and catcher Yadier Molina at the next at-bat likely went something like this:

Molina: Hey, don't give this guy anything to hit right now.

Gant: (throws first-pitch strike)

Yadi: What'd I just say?

Gant: But ... it's Scooter Gennett.

Yadi: Oh, I know.

Gant: Well, it's 3-1, and I'm not going to just walk Scooter Gennett. Maybe I'll try the exact opposite spot from last time.

From the beginning of his career until he joined the Reds, Gennett posted an ISO of .079 on pitches in that location. He could have taken it and made the count full. In fact, it was far enough to the edge that it might have earned him a walk. But no, Super Slugger Scooter Gennett went oppo taco.

When the eighth inning rolled around, it was 11-1 Reds, and something named John Brebbia had taken the hill for the Cardinals in the mop-up role. The bullpen's mantra at this point seemed to be: "Let's just go home."

There are two outs, and you've sneaked two strikes past a player who's 4-for-4 with three home runs. You could certainly go out of the zone here. Nah. OK, maybe go off-speed, though. Double nah.

That's the bunny hop of someone who tempts fate.

(Graphics courtesy: Baseball Savant)
(Images courtesy: MLB)