The Tampa Bay Rays are taking a relatively novel approach to divvying up innings between starters and relievers. Injuries have robbed the team of Alex Cobb for the season, Matt Moore and Drew Smyly for much of the year, and Jake Odorizzi for a time as well. Despite those problems, the team climbed to a 41-32 record a few weeks ago thanks to a splendid season from Chris Archer, good seasons from Odorizzi, Nate Karns — and even Erasmo Ramirez has pitched in to help the team form a solid rotation. The team has slid back to the pack in the difficult-to-decipher American League East, but still finds itself just two games back of the Yankees after losing nine of their past 12 games. Rays’ starters have been effective, but have not pitched deep into games, leaving the outcome of many games to a set of inexperienced relievers who have been shuffled between the big-league club and the minors all season long.

The Rays’ strategy appeared to be related to to two potential issues. First, the rotation was so depleted at the beginning of the year, they twice pitched bullpen games, letting Steve Geltz pitch a couple innings until his spot in the batting order. The other problem is that the deeper pitchers tend to pitch into games, the worse they tend to do. Getting a pitcher out of the game after two times through the lineup can limit damage to the starters and it can work so long as the team has a deep and effective bullpen. The Rays’ starters have averaged just 89 pitches per start, the fewest in MLB. Ted Berg noted a few weeks ago that the Rays were on pace for the second-lowest total of plate appearances (to the 2012 Colorado Rockies, who experimented with a four-man rotation) three times through the lineup in the last decade.

The graph below shows innings pitched by every bullpen this season.



The Rays have thrown more innings out of the bullpen than any team this season, and at their current pace, they would end up with just over 546 innings on the season. Reaching that many innings is not exactly unusual; in fact, it’s been done 25 times over the past ten years. What would be unusual is a bullpen throwing that many innings on a winning team. Of the 25 teams to have recorded at least 546 bullpen innings over the past ten years, only two teams have ended the season with winning records: the 2009 Los Angeles Dodgers and the 2007 San Diego Padres. Both of those teams had very good bullpens. The Padres team put up a 3.06 ERA and 3.71 FIP that were both the best in major-league baseball that season, while the Dodgers 3.14 ERA and 3.74 FIP were first and third, respectively, on their division-winning 2009 team.

Deciding when to remove a starter can be a difficult proposition, especially when the bullpen arm is not going to be one of the team’s best relievers. Per Baseball Reference, the league overall has produced the highest ERA (4.05) and FIP (3.98) between the fourth and sixth innings — this, as compared to innings one through three and seven through nine, despite the first inning being the highest-scoring inning in MLB. The Rays have managed to do very well in the first three innings, with a 3.32 ERA and 3.16 FIP, but have kept the pace results-wise in innings four through six, with a 3.04 ERA but also a 3.76 FIP that does not match the results. The Rays have actually had the biggest problem at the end of games as they had been giving high-leverage innings to Kevin Jepsen before settling on Brad Boxberger as the closer with Jake McGee’s return also helping matters.

Overall, the Rays bullpen does not figure to rank too highly in ERA or FIP this season, and the team is nowhere near the level of the Dodgers or Padres teams mentioned above.



That the Rays could have mediocre overall numbers out of the bullpen to go along with an average offense and still post a winning record is a testament to the starting rotation, but the bullpen’s successes have been well-timed. The team leads the majors in shutdowns, recorded when a reliever enters a game and the win expectancy increases by at least .06 during his appearance. Shutdowns are context-based, generally requiring both a close game and a good result. The Rays’ relievers have been provided ample opportunities in close games, with an average leverage index entering a game that’s the highest in the American League.

The Rays bullpen has generally taken advantage of those opportunities: the club possesses the highest percentage of bullpen appearances that have resulted in shutdowns in MLB.

Despite the subpar FIP and ERA for the bullpen, Rays relievers have been a net-positive results-wise with a WPA of 0.97. While the high number of innings would lead to the natural conclusion that the bullpen has been tremendously overworked, that has not been the case for Tampa. No pitcher is on pace for more than 70 innings, and while the number of games pitched without rest is high, it is not outlandish, per Baseball Reference.

Those numbers have increased considerably in the last few months, but the Rays have avoided overworking relievers by increasing their quantity. The Rays have 21 pitchers on their 40-man roster and only the injured Grayson Garvin has yet to throw a pitch for the big-league team this season. Including position players Nick Franklin and Jake Elmore, 21 relievers have made an appearance for the Rays this year. Fifteen relievers have made more than five appearances.

The Rays’ success might not be sustainable this season, but they are certainly trying to make the most of what they have. Despite a less than stellar bullpen ERA and FIP, the bullpen has been effective for the Rays this season in taking the load off of a depleted rotation. Our current playoff odds give the Rays a roughly one in five chance of making the playoffs, which is basically where they were to start the season. The projections had the Rays as about a .500 team and so far the season has played out the same way. They still need more than a few things to go right the rest of the way to find themselves in the playoffs, but given the injuries and how much they’ve had to rely on the bullpen, the team should be fairly happy with how well they have played despite their recent downturn.