The secret to Royals pitcher Ian Kennedy’s fast start as a reliever in 2019

Before getting into the specifics — and pinpointing some of the reasons for his revival in the bullpen this year — Ian Kennedy wants to discuss Clayton Kershaw.

Or, more specifically, what it’s like to face the future Hall of Famer.

Kennedy was required to hit in a majority of his starts while playing for National League teams from 2010-15 ... and that fact, he says, made him a better pitcher. By doing that, he could better understand what hitters saw, and why — to the eye — certain pitches were more difficult to hit.

Which brings us back to Kershaw. Kennedy remembers what it was like, after getting a bunch of pitches low, to see Kershaw elevate his fastball.

A third-inning at-bat from Aug. 30, 2012 is one example.

“It’ll say 92-93 (mph), but it looked like 98. You’d swing right through it, and you’re like, ‘What?’ You look on video, and you’re this far below it,” Kennedy said, holding his hands a few inches apart. “The ball just carries.”

Behold the power of a high-spin, rising fastball.

And also one of the reasons for Kennedy’s increased success while pitching from the bullpen this year.

Kennedy’s overall numbers, so far, have been impressive. He ranks fifth out of all MLB pitchers in Statcast’s all-encompassing expected weighted on-base measure, while also sitting eighth in WAR among all relievers at Fangraphs.

The biggest reason for the turnaround: Kennedy’s fastball has been much more effective than a year ago.

While not a perfect measure, Pitchf/x’s pitch value numbers give us a good look. Last year, Kennedy’s four-seam fastball ranked 95th out of 140 pitchers with at least 100 innings. This year, the pitch ranks 48th out of 329 pitchers with 10 innings or more.

This is important. Kennedy has always been a pitcher who relies heavily on his four-seam fastball, and this year, he’s upped that pitch’s usage from 56% to 63%.

“At times, I probably have had too much confidence in it,” Kennedy said with a smile. “In the past, it’s bitten me.”

This year, it hasn’t.

And the simplest way to explain it is that Kennedy’s mistakes aren’t getting hit like they once were.

Kennedy has always been a believer in throwing down and away frequently, believing only the very best MLB hitters — think guys like Mike Trout and J.D. Martinez — have the power and skill level to drive that ball with power the opposite way.

The numbers back this up. Here’s a look, via Statcast, at the slugging percentage for right-handers who faced Kennedy in 2018 (from the catcher’s viewpoint).

Kennedy 2018

The blue circle indicates that low-and-away zone to righties, who weren’t able to generate much force when Kennedy was able to hit that spot.

When he missed, though? The dark red on the chart shows that Kennedy was hit hard then, with opponents crushing those offerings that were elevated.

Let’s look at the same chart for 2019.

2019 Kennedy vs. righties

It’s still a small sample size, but Kennedy has gone from a pitcher who was getting blasted on high pitches to one who can make mistakes in the zone without paying for it.

We can note a few differences from last year. The most obvious is that Kennedy is pitching out of the bullpen, which allows him to go more max-effort during his outings; as a result, his fastball velocity has ticked up from a 91.9 mph average last year to 93.2 this season.

There’s also appears to be more life to his arsenal in 2019. The best way to compare this is to look at similar pitches from last season to this one.

Here’s an example: Kennedy throwing an up-and-in four-seam fastball to different right-handed hitters on Sept. 21 last year and April 10 this season.

The naked eye appears to indicate a small but important difference with the movement. One fastball is at 90 mph, with gravity appearing to pull it down slightly at the end right into the barrel of Ronny Rodriguez’s bat. The second one is traveling 94 mph, with what appears to be more of a rise at the finish to get a dangerous hitter (Edwin Encarnacion) to swing underneath.

And this appears to be the biggest theme with Kennedy in 2019: Whether he hits his exact location or not, he’s been able to generate whiffs by getting players to swing below his fastball.

The results seem to reflect this shift. Kennedy has allowed a .269 slugging percentage on his four-seam fastballs this year, which is less than half of what he surrendered a season ago (.557).

In short, Kennedy’s longheld belief appears to still be true, just as it was when facing Kershaw in 2012.

A rising fastball, when it’s on, remains an awfully tough pitch to hit.

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Jesse Newell — he’s won an EPPY for best sports blog and previously has been named top beat writer in his circulation by AP’s Sports Editors — has covered KU sports since 2008. His interest in sports analytics comes from his math teacher father, who handed out rulers to Trick-or-Treaters each year.