SEATTLE, WA - MAY 04: Mike Leake #8 of the Seattle Mariners pitches in the first inning against the Los Angeles Angels during their game at Safeco Field on May 4, 2018 in Seattle, Washington. (Photo by Abbie Parr/Getty Images)

For an impossibly hot Mariners team, Mike Leake quietly pulled off one of the unlikeliest events of the 2018 season.

At 55-31 and freshly minting what would be their longest win streak of the year, the Seattle Mariners were steaming into Independence Day. But the now-familiar narrative was building — without their best player, the Mariners were the team to root for, but they were overperforming. Eight straight games won by no more than 3 runs seemed to signal a season-long fairy tale or an inevitable collapse depending on your perspective, so while all eyes were on the Mariners that day, it’s understandable that not everyone was paying attention to Mike Leake.

Nearly 40,000 people came out to see the Mariners square off against the Angels on July 4th.

They saw the Mariners lose 7-4. They saw Mike Trout take two intentional walks. They saw Mike Leake strike out Andrelton Simmons. And…

…they what now?

Okay, so it wasn’t a once-in-a-lifetime, perfect-game-spoiled-by-a-missed-call type of event, but Mike Leake pulled off one of the more unlikely strikeouts in recent memory last year.

Unfortunately, like most of Leake’s strikeouts, this one went by without much more than a little punctuation from broadcaster Dave Sims.

I say that shouldn’t be the case.

In all of its glory, here it is:

A little sinker in on the hands and down he goes.

It’s the second of three times that Leake has struck out Andrelton Simmons in his career. He’s gotten him 3 times in 30 plate appearances, in fact, which is a higher rate than Simmons’ career average.

In turn, Simmons OPS’s 1.100 against Leake. It’s a trade-off.

Part of what makes this particular strikeout peculiar though is that, by season’s end, among all qualified batters in 2018, Andrelton Simmons had the lowest K% in the league (7.3%). And — you guessed it — among all qualified pitchers, Mike Leake had the lowest K% in the league (15.2%).

What’s more incredible is that coming into this game, Simmons had an bonkers 4.5% K% while Leake settled in at a career-low 14.9%.

This was a match made in bat-to-ball heaven.

Two of the most contact-oriented forces in baseball were facing off with their strikeout rates having already trended in the same direction — down. At this point in the season, there was no routine outcome less likely than Mike Leake striking out Andrelton Simmons, but that is exactly what happened.

He struck him out. He struck him out swinging.

Of course, most strikeouts are of the swinging variety, but this fact will become a little more interesting later.

Through July 3rd, Andrelton Simmons had struck out just 14 times, and of those, 10 were swinging strikeouts per Baseball Savant, giving him a 3.2% swinging-strikeout rate.

In the same time, Mike Leake posted an 11.3% swinging-strikeout rate with 66 total strikeouts.

Likely, neither guy nor any person in the stadium was expecting a strikeout here and for good reason. That’s probably partly why Leake threw an 0-2 sinker in the first place.

If we wanted to estimate the probability of this strikeout though (using Bill James/Dallas Adams’ log5 formula) — and we do — we must first find the league average swinging-strikeout rate. We do so for the entire league prior to July 4th using data from Baseball Savant:

With 15254 swinging strikeouts over 97413 plate appearances, the league-average swinging-strikeout rate at the time was roughly 15.7% (15254/97413).

Adopting the log5 formula from the link above, we estimate that the probability of Mike Leake striking out Andrelton Simmons swinging at this point in the season was just 2.3%.

If that doesn’t seem excitingly low to you, how about some context?

Typically, division rivals play each other 18 times every season. Given that series are (again, typically) played 3 or 4 games at a time, a starter could reasonably make 5 starts against the same team in a given year without any funny business.

At a generous 4 plate appearances against a starting pitcher per game over 5 starts, it’s possible that a pitcher-batter pairing could square off something like 20 times in one season.

If Simmons and Leake were to do this, holding everything else constant, there would still be over 2 years between swinging strikeouts on average.

If they only matched up 12 times per season like they did last year, we would expect Leake to get Simmons swinging once every 3 and two-thirds years.

At the rates they were going at the time, they could have spent concurrent 19-year careers in the same division, and Leake would have struck Simmons out swinging all of 5 times.

Now, here is where the pitch selection makes this even more improbable.

I mentioned earlier that Leake struck out Simmons swinging with his sinker.

Well, part of what makes Simmons one of the best contact hitters in the game is his stinginess against fastballs, and certainly, sinkers are no exception.

According to Brooks Baseball, Simmons has whiffed on just 5.85% of his swings against sinkers/two-seamers over his career.

In 2018, his whiff rate against sinkers going into July 4th was a ridiculous 1.04% over 225 pitches.

Roughly, he had swung at 100 sinkers and whiffed just once prior to this at-bat, and Mike Leake simply said: “Make it twice.”

And so it went.

On pace to log a K% not seen from a qualified batter since Placido Polanco in 2005, the stingiest strikeout-avoider in the league stepped up against one of the most strikeout-deficient pitchers in the game, and on a 2-strike pitch that he never misses… he struck out.

The final kicker? Leake got Simmons to whiff on 3 straight pitches.

Good morning.

Good afternoon.

Goodnight.