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The Tampa Bay Rays are trying out a new type of pitcher

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What do you call a reliever who starts games?

Tampa Bay Rays v Boston Red Sox Photo by Omar Rawlings/Getty Images

Here’s a pop quiz. Who pitched the most innings for the Triple-A Durham Bulls last year? Ryan Yabrough at 157.1 over 26 starts. Great job!

Now who pitched the second most? Yonny Chirinos, at 141 innings in 22 starts. You’re acing this!

And third? Brent Honeywell of course. He completed 123.2 innings with his 24 starts, may his arm heal well.

Now this is the hard one. Who pitched the fourth most innings for the Durham Bulls in 2017?

You probably said Andrew Kittredge, but only because of that picture of him up above. That same Andrew Kittredge who already has two “starts” in 2018 and will make his third later today. Kittredge gave Durham 68.1 innings, despite “starting” only two games, and he contributed an additional 15.1 innings to the major league club.

Generally, a reliever being asked to pitch 83.2 innings in a single season would raise a red flag as a possible instance of pitcher abuse. Had Kittredge logged those innings in the majors, he would have been third in reliever innings pitched, behind only Yusmeiro Petit and Chris Rusin. But the way the Rays used Kittredge wasn’t like how the Athletics used Petit or the Rockies used Rusin.

Look at how many days each of them had between appearances.

Kittredge almost never pitched on back-to-back days, and he only pitched with one day of rest between appearances ten times. His appearances were spaced out. This spacing is even more clear when looking at spans of three appearances.

Both Rusin and Petit had a plurality spacing of three appearances in five days. Kittredge’s plurality spacing for three appearances was seven days.

Kittredge’s role in 2017 was to throw a lot of innings for a reliever, usually getting more than three outs, on a semi-regular schedule. For what it’s worth, Jeff Ames (now in the Nationals system) and Chih-Wei Huh threw on similar schedules in Durham.

Yarbrough, Chirinos, and Austin Pruitt all made the major league team out of Spring Training this year as the headlining part of the Rays non-traditional four-man/three-man rotation. That seemed to cause an uproar, but they play a role that should be instantly recognizable to a baseball traditionalist—it’s called a “swing man.” It’s a role for a pitcher who could start, and generally has in the minors or in the majors before, but who is instead sent to the bullpen to soak up innings when needed. Breaking camp with three swingmen may not be common, but by doing so the Rays haven’t necessarily done anything new.

If we are looking for innovation, however, maybe we should be looking at Andrew Kittredge and the role he has been asked to play. What do you call a pitcher who can face six batters every few days? More importantly, what do you do with him?


Kittredge isn’t the type of pitcher that wows on first sight.

He throws a low-to-mid-90s four-seam fastball (average of 94 mph, per Brooks Baseball), that’s very straight, which helps set up his above-average mid-80s slider. The slider is Kittredge’s money pitch.

Slider quality can be a complicated thing to talk about, but overall it’s a relationship between velocity and movement—in general, more of both is better.

Below, from Baseball Savant, is a comparison of sliders across the major leagues in 2018, with Rays pitchers highlighted. Pitch velocity is on the Y axis and spin rate is on the X axis. Keep in mind that how that spin rate is transformed into movement also depends on the angle of the spin with relation to the flight of the pitch, so not all spin rate comparisons are quite apples-to-apples, but looking at spin rate rather than movement eliminates a dimension and does help simplify the graph.

Kittredge has neither the exceptional spin rates of Sergio Romo and Chaz Roe, nor the ability to throw good spin with top velocity, like Chris Archer and Austin Pruitt (!). But what he does have is a mixture of both that puts him in or near the top-third of slider quality overall, and he’s willing to throw that slider early and often. In his short time in the majors, Kittredge has thrown his slider 60% of the time, and his fastball only 37% of the time, per Brooks (the rest of the pitches are a handful of changeups).

He’s thrown that slider with nearly equal frequency in all counts, to both handedness of batters. Batters have missed on 30% of their swings, and have hit it on the ground for 59% of their balls in play against the pitch. When the Rays acquired Kittredge from the Mariners before the 2017 season, they had him throw that slider a bit more, and at least one result was obvious—his GB%, which had spent most of his career in the 30% to low 40% range jumped up to 53%.

Over his short time in the majors, Kittredge has had a reverse wOBA split, and a normal xFIP split. In 2017, his minor league OPS split was reversed, but in 2016 it was normal. The sample sizes are small enough though that it makes more sense defer to overall baseball knowledge, rather than looking for Kittredge to be an exception: Right-handed pitchers who rely on their slider, in general, are better at getting out right-handed batters.


So how should Kevin Cash and the Rays use Andrew Kittredge? What does one do with a reliever who is neither a dominant back-of-the-bullpen one-inning type nor a converted starter who can go long when you need him to?

Option One: The Early Hook (use him proactively when the matchup is right)

It’s now well-established that hitters are more likely to succeed against a pitcher the more times they see him. For all but the best starting pitchers (and depending on situation, for them too), pulling them before they face an opposing lineup for a third or fourth time is a good way to limit runs.

The problem is that aggressively pursuing this strategy over the course of the season, which shifts innings from the starters to the bullpen, can potentially overtax that bullpen. If the relief pitchers are tired, or if they’re guys who should probably still be in Triple-A but who have been called up because the better relief pitchers are tired, then those relief pitchers are not going to actually be the better option. As the workload stacks up, the break-even point of when to pull a starter moves later.

This is where Kittredge comes in.

  1. Assume his minor league record indicates that he’s able to pitch a lot of innings, at least as long he’s given them in short stints with a bit of rest in between.
  2. Assume that his handedness, repertoire, and track record indicate that he’s a good option for medium-leverage situations against right-handed batters, and for medium-to-low-leverage situations against left-handed batters.
  3. Assume that the Rays don’t want him pitching when the leverage is high (that’s Alex Colome, Jose Alvarado, Chaz Roe, and Sergio Romo).
  4. Assume that the Rays don’t want him facing the best lefties very often, period.

That leaves a pretty specific situation where the Rays do want to use Kittredge. To tap into his value, which lies partly in his ability to shoulder a heavy workload, Cash will need to go to him whenever the situation is right. Sometimes that might mean pulling a starter a few batters earlier than might be otherwise necessary, to take advantage of a matchup for Kittredge. Sometimes that might mean using Kittredge even when Roe or Romo are rested and would be the better option if it were game seven of the World Series, because it’s not game seven, and doing so will keep those other guys rested and available for another situation when the innings start to stack up.

The value gained from efficient application of pitching resources to take advantage of comparative advantage may not be apparent in every game, but will assert itself over time.

Kittredge doesn’t offer much as the last arm out of the bullpen. Few relievers do. But if he can pitch a little bit better than that, and if the Rays are willing to trust him, he can offer more.

Option Two: The Opener (use him to create the matchup)

Forget the Times Through The Order Penalty, starting pitchers have a First Inning Problem.

Here, from the FanGraphs splits tool, is the wRC+ by inning across all of MLB in 2017.

Offense By Inning, 2017

Inning wRC+
Inning wRC+
1 106
2 92
3 100
4 105
5 102
6 99
7 91
8 90
9 82

It does make sense that the first inning would be the one most tilted towards the offense. Opposing managers know who’s starting, so they stack the top of their lineup with their best hitters, and with the ones who have a favorable matchup against that particular starter. Those good hitters, with their good matchup, always get at least one crack at the starting pitcher in a situation of their manager’s choosing, and that always happens in the first inning.

But what if it didn’t?

Ryan Yarbrough, a lefty, was originally supposed to start today. Yarbrough was a starter in the minors, and based on his early season usage, it seems like the Rays would like for him to face an opposing order two times or so. His longest appearances in 2018 have been just over four innings.

Probably, the plan was for Yarbrough to work as long as he could, and then for the Rays to go to Kittredge if the situation was right. But yesterday it was announced that Kittredge would pitch the first inning. Yarbrough will still be available.

Is Kittredge —> Yarbrough meaningfully different than Yarbrough —> Kittredge? Does swapping them help with The First Inning Problem?

Consider the options for the top of the Blue Jays order:

  • Josh Donaldson, the Blue Jays best overall player, hits in the two spot. He’s scary for anyone, but he really mashes lefties.
  • Justin Smoak is on the team to mash lefties, and does little else.
  • Teoscar Hernandez, Lourdes Gurriel, Kevin Pillar, and Russell Martin are all everyday players who are distinctly better against LHP.
  • Curtis Granderson is the anti-Smoak, batting first against right-handed starters but usually taking a seat against lefties.
  • Yangervis Solarte is a switch hitter, but he’s been better over his career facing righties.

If Yarbrough starts, then John Gibbons gets to set the top of his lineup full of lefty-mashers, knowing that they’ll get the perfect sequence in the first inning, and that they’ll get at least one more shot at Yarbrough before the game turns into a matchup puzzle for the Rays bullpen. But if Kittrredge starts, Gibbons has to make a choice. Does he bat Granderson first and then pinch hit for him in the fourth inning? Does Solarte bat third, where there’s a better chance Yarbrough gets to face him twice?

Does Gibbons play to optimize the first inning, or or does he play to optimize the total number of plate appearances? Switching the order of Yarbrough and Kittredge makes it so that those two optimizations are not the same lineup.

The interesting thing about “The Opener” option is that the comparative advantage gained by starting Kittredge might not be reaped by Kittredge at all. Yes, Kevin Cash can be certain that he’s giving Kittredge a medium-leverage opportunity—the leverage at the start of a game is always one, or average, and in that sense he’s proactively deploying Kittredge in the situation the Rays want him pitching. But by doing so, he’s giving up control over the handedness matchup.

Maybe that’s a bluff, but I’m not sure Cash cares if Gibbons calls it, because if Gibbons calls the bluff on Kittredge, he should theoretically be either burning through is bench (and incurring pinch-hit penalties) or giving Yarbrough a better matchup than he would otherwise.


When the Rays broke camp with Yonny Chirinos, Ryan Yarbrough, and Austin Pruitt, but without handing the any of them the title of “starter,” the world of baseball punditry went crazy. It was an indication that the Rays were up to something, and depending on your point of view, were either a fun and innovative bunch trying to get to the future of baseball first, or an utter disgrace to the game.

The silliest thing about all of that uproar was that there really wasn’t anything that different going on with the three Rays swingmen. Chirinos and Yarbrough were used like fifth starters (although the fifth spot was occasionally skipped when the schedule allowed it), and after a few games in which the Rays got him more fully stretched out, the decision was made to call Chirinos the thing that he already was.

If you ignored all that noise, good for you. It’s generally a good idea to ignore bombast.

But pay attention to what the Rays do with Andrew Kittredge. That’s where there’s something interesting going on.