The Mariners approach peaked against Shane Bieber

Mariners hitters had their best game of the year on Sunday.

I wrote recently about the Mariners approach at the plate. Basically, their plan last month was to swing at heart pitches and not swing at anything else.

To measure this approach, I took the ratio of swings dedicated to heart pitches and divided it by the rate of heart pitches. This is what I call the “Heart Swing Index.” They performed very well in this metric despite facing tough pitching.

On Sunday, against reigning Cy Young Award winner Shane Bieber, the Mariners had their highest index rating to date.

Not only was it their best performance of the season, it was among the top 2% of games in MLB all year.

Mariners hitters dedicated 46% of their swings were to heart pitches. That‘s not inherently impressive, but they saw just 24% of pitches in the heart region. In comparison, they saw 45% of pitches in the shadow region and swung at those pitches just 36% of the time.

Here’s are the pitches they saw:

And here are their swings:

Cleveland pitchers wore out the edges of the plate, and Mariners hitters didn’t budge from their heart-focused approach.

Even Bieber acknowledged it after the game:

Now, we already knew teams had picked up on the Mariners swing tendencies — no team in MLB has seen fewer heart pitches all year — but it’s cool to see an elite pitcher explicitly confirm the scouting report.

Scott Servais sounded impressed with the performance in an interview with Ryan Divish after the game:

“….He makes mistakes in the middle of the plate,” Servais said. “I just watched his last outing, and he’s really, really good, but nobody’s perfect. You’ve got to be ready to hit, you’ve got to be ready to hit from pitch one, trying to control the outside corner, especially if you’re a right-handed hitter. He commands it very, very well. But he still makes mistakes. We’ve got to be ready to capitalize on them because there’ll be a few there, there will be at least one guaranteed.”

He continued:

“Hitting is contagious,” he said. “When you get a couple of guys going, it starts to spread up and down the lineup. It’s just a better vibe and feeling. I thought the last couple nights we did some nice things offensively and I was hoping it would carry into today. I certainly respect their starter and what he’s done, but we were ready. The most impressive thing today is we didn’t chase. We just grinded, and really made him throw a ton of pitches.”

Here’s one of my favorite at bats from the game:

Lewis takes a slider off the edge of the plate. He chases and fouls off a high fastball. He takes another tough slider outside. He fouls off a heart slider to even the count. Then he gets the mistake he’s waiting for — a fastball in the heart region — and drills it into left field at 107 mph.

What I love about this plate appearance is that Lewis wasn’t perfect. He chased a high fastball. He fouled off a heart pitch. But his approach allowed him to hang in there and get the middle-middle fastball. That at bat could have easily gone off the rails and it didn’t.

An interesting note: the Mariners excellent pitch selection Sunday followed one of their worst performances of the year Saturday, which followed one of their best performances of the year Friday, which followed one of their worst performances of the year Thursday.

Maybe it’s simpler to show their pitch selection during the Cleveland series by league percentile rank:

• Thursday: 6th
• Friday: 90th
• Saturday: 11th
• Sunday: 99th

Here’s the chart:

Technically, the metric shown here is a little different than at the top. I like to isolate just pitches seen in the “true zone” — the heart and shadow regions of the plate. I think it does a better job of getting at the spirit of what I’m trying to measure.

The steady excellence of April has been replaced by a series of highs and lows in May. The rolling average line doesn’t quite know where to go. If it feels like the Mariners have alternated between competent at the plate and entirely overwhelmed, the numbers back that up — no team lands more often in the top 25% or bottom 25% of games.

And it makes sense. As I mentioned above, no team has seen more shadow pitches than the Mariners this year. Opponents are relentlessly pounding the edges of the plate against them.

That can work to their advantage when they lay off those pitches and create good counts and make contact on heart swings. But when they swing out of the zone or miss the middle-middle mistakes, they fall behind and are forced to further expand the zone.

The Mariners are sort of proving that hitters have a ton of control over where they’re pitched and the size of the zone. I think this is what is referred to as Controlling the Zone.

###