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The Rays rotation: Quality over quantity

The Rays starting pitchers has been excellent so far in 2015, despite throwing an unusually low number of innings. As it turns out, the Rays may have good reasons to limit the innings of their starting pitchers.

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Adam Hunger-USA TODAY Sports

The Tampa Bay Rays have surprised a lot of people by managing to remain competitive so far in 2015. After a disappointing 77-85 season in 2014, expectations were low for the Rays. They didn't look like the same team that had made the playoffs four times from 2008-2013, in large part because David Price, Joe Maddon, and Andrew Friedman had moved on to different teams.

Going into Tuesday, the Rays record was 43-41, which puts them right in the thick of the AL East race. They have managed to play slightly above .500 despite being without four of their starting pitchers at various points throughout the year. Jake Odorizzi has been on the DL for nearly a month with an oblique strain. Matt Moore made his first start of the season last week after returning from Tommy John surgery. Drew Smyly made just three starts this year before his season was ended due to shoulder surgery. And Alex Cobb didn't even make an appearance this year before having season-ending Tommy John surgery.

Despite this, the Rays starters have been excellent this year. Yes, having Chris Archer in the rotation certainly helps, but the Rays have have gotten surprising contributions from players like Nate Karns, Erasmo Ramirez, and Alex Colome. The Rays rotation is 4th in the majors in ERA (3.12), 6th in FIP (3.45), and 9th in xFIP (3.56).

What makes this success so interesting, though, is that the Rays starters have averaged just 5.6 innings per start, fourth worst in all of baseball. As you can probably guess, this is very unusual. After all, it makes intuitive sense that a starting rotation that is good at preventing runs is more likely to pitch a higher quantity of innings.

As you can see in the table below, that does, in fact, appear to be the case.

Team Innings Per Start ERA FIP xFIP
Mets 6.20 3.57 3.49 3.47
White Sox 6.19 4.14 3.57 3.64
Cardinals 6.18 2.79 3.26 3.41
Pirates 6.16 3.08 3.14 3.30
Athletics 6.14 3.00 3.37 3.76
Angels 6.12 3.78 4.15 4.18
Tigers 6.09 4.34 4.14 3.98
Dodgers 6.07 3.21 3.45 3.16
Mariners 6.05 3.68 3.84 3.74
Nationals 6.04 3.67 3.11 3.50
Astros 6.01 4.01 3.77 3.76
Indians 5.97 4.30 3.51 3.29
Braves 5.95 3.74 3.95 4.08
Cubs 5.94 3.54 3.37 3.22
Reds 5.91 4.09 4.41 4.09
Padres 5.91 4.13 4.00 3.56
Giants 5.89 4.07 4.07 3.89
Twins 5.88 3.85 4.02 4.09
Brewers 5.82 4.78 4.42 4.04
Blue Jays 5.82 4.58 4.55 4.35
Yankees 5.77 4.32 3.82 3.55
Red Sox 5.74 4.76 3.84 3.97
Rangers 5.73 4.11 4.30 4.53
Diamondbacks 5.71 4.63 4.36 4.08
Marlins 5.69 4.21 4.18 4.22
Orioles 5.66 4.15 4.39 4.17
Rays 5.63 3.12 3.45 3.56
Phillies 5.58 5.24 4.65 4.35
Royals 5.53 4.40 4.17 4.42
Rockies 5.51 4.93 4.81 4.42

The rotations averaging the most innings per start, such as the Mets, Cardinals, and Pirates, are some of the best rotations in all of baseball. On the flip side, the worst rotations in baseball are generally found near the bottom of this table, averaging below six innings a start.

By ranking team rotations by innings per start, it is pretty easy to see how different the Rays rotation is from the other rotations averaging a similar number of innings per start. While the Rays' starting pitchers have a combined ERA of 3.12, only one other rotation in the bottom half in innings per start has an ERA below four (the Twins at 3.85). Similarly, the few rotations that compare to the Rays in terms FIP and xFIP are all found near the top of the table, averaging around six or more innings per start.

So why are the Rays starters throwing so few innings despite pitching so effectively? The Rays haven't publicly said anything about an overarching strategy with starting pitcher usage, but I wouldn't be surprised if the team is intentionally pulling starting pitchers from the game early in order to avoid the times through the order penalty. As Mitchel Lichtman pointed out years ago in The Book: Playing the Percentages in Baseball, starting pitchers become less effective the more times they face a lineup in the same game. According to Lichtman, pitchers, on average, allow a wOBA of of .345 the first time through the order, but this increases to as high as .362 the third time through the order. By removing their starting pitchers from the game early, the Rays are taking away any advantage opposing hitters may gain from seeing a starting pitcher for a third time.

Of course, this kind of arrangement forces the bullpen to pick up a higher number of innings, and it could lead to relievers getting overworked and becoming less effective. Indeed, the Rays bullpen as a whole has struggled in 2015, posting a replacement level performance (3.88 ERA, 4.28 FIP) in a league-leading 283 1/3 innings. However, the Rays bullpen struggles are probably not due to relievers getting overworked.

As Ian Malinowski recently pointed out in an excellent piece over at D Rays Bay, the Rays have not overworked any individual relievers because they have been continually shuttling relievers back and forth between Triple-A Durham and the major league bullpen. The Rays have received contributions from twenty different relief pitchers this season (not including Nick Franklin), and eleven of these relievers have pitched at least ten innings. And while the Rays bullpen has thrown more innings than any other bullpen in the major leagues, no individual Rays reliever has thrown more than 34 1/3 innings. The two relievers who have that innings total, Steven Geltz and Kevin Jepson, rank 58th among all major league relievers in innings pitched.

Injury concerns could be another factor in the Rays decision to limit the innings thrown by their starting pitchers. As Jeff Passan wrote about last month, the Rays recently installed Kinatrax technology at Tropicana Field in order to analyze biomechanical data during a game.

Passan writes:

"Kinatrax uses ultra-high-speed cameras and aims to capture the sort of biomechanical data that previously necessitated the placement of reflective markers on different body parts. Should Kinatrax do what it purports to, it would revolutionize baseball by offering looks at pitchers' in-game biomechanics instead of those revealed in laboratory settings....While Kinatrax's current version measures the angles and velocities of bones and joints, future versions hope to calculate stress and strain on tendons and ligaments - a potential landmark leap that theoretically would show signs of pitchers whose ulnar collateral ligaments are in peril.

It appears that the Rays are using Kinetrax to analyze their pitchers and have a better understanding when they are most at risk of getting injured. Perhaps the Rays can identify when a pitcher's mechanics begin to deteriorate and remove him from the game before he does anything that could negatively impact his long-term health. It is also noteworthy that one of the Rays' analysts is former Hardball Times writer Josh Kalk, who specialized in using PITCHf/x data to analyze pitcher injuries.

For several years now, the Rays have been known as one of the most analytically-minded organizations in all of baseball, so we probably shouldn't be too surprised to see them managing their pitching staff in such a unique way. Baseball has certainly been trending towards shorter starting pitcher outings and more specialized bullpens in recent years, especially in the postseason. While Andrew Friedman and Joe Madden may be gone, the Rays organization is still very much the same, continuing to look for creative ways to gain an edge on other teams and remain competitive despite all the factors working against them.

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Nick Lampe is a contributor at Beyond the Box Score and Viva el Birdos. You can follow him on Twitter at @NickLampe1.