In Seth Lugo and Robert Gsellman, the Mets have two former starters pitching well out of their bullpen. While that transition would have recently been considered a demotion, it’s not clear that that’s the case today. In fact, given relievers’ increasing prominence in the game, the transition could end up paying off for Lugo and Gsellman if they continue to be effective bullpen arms for the Mets.

First, it’s clear that both Lugo and Gsellman are more effective as relievers than they are as starters. Throughout their careers, both pitchers’ ERAs out of the pen are nearly half of what they are in the rotation. As their adjusted ERAs indicate, Lugo and Gsellman are basically league average when starting games; as relievers, both are around 40% better than league average at preventing runs from scoring. (All stats are current as of Wednesday morning.)

Lugo and Gsellman Pitcher Starter IP Reliever IP Starter ERA Reliever ERA Starter ERA- Reliever ERA- Pitcher Starter IP Reliever IP Starter ERA Reliever ERA Starter ERA- Reliever ERA- Seth Lugo 145.1 48.1 4.09 2.23 100 58 Robert Gsellman 156.2 38.0 4.60 2.37 112 63

It makes sense that pitchers would generally be more effective relievers than starters, as relievers can throw harder and use all their best stuff in shorter bursts. It’s also consistent with the recent history of pitchers who performed in both roles. In the 20 years from 1998 to 2017, 75 pitchers threw at least 200 innings as both starters and relievers. (You can view and play around with the list here.)

As starters, those 75 pitchers posted an average ERA of 4.81, exactly a full point higher than their 3.81 average ERA as relievers. Like Lugo and Gsellman, those pitchers were league average or slightly worse as starters (111 ERA-), but much better than average coming out of the pen (89 ERA-). Here are a few well-known examples (including some former Mets) and how they performed in each role:

As starter vs. reliever Pitcher Starter IP Reliever IP Starter ERA Reliever ERA Starter ERA- Reliever ERA- Pitcher Starter IP Reliever IP Starter ERA Reliever ERA Starter ERA- Reliever ERA- Joe Blanton 1550.1 212.2 4.47 3.74 108 91 Ryan Dempster 2150.2 230.2 4.38 4.07 104 90 Elmer Dessens 775.2 367.0 4.53 4.02 101 93 LaTroy Hawkins 364.1 942.2 5.92 3.28 121 75 Braden Looper 567.1 605.2 4.75 3.58 113 85 Derek Lowe 2208.0 390.2 4.12 3.15 97 67 Darren Oliver 891.2 543.0 5.52 3.06 117 70 John Smoltz 1149.2 260.1 3.41 2.41 78 57 C.J. Wilson 1169.2 257.2 3.76 3.65 94 79 Kerry Wood 1114.2 262.1 3.69 3.59 86 84

These disparities, coupled with the premium that teams are placing on quality relief pitching, raise an interesting question: Does it pay more to be an average, back-end starter, or a quality, late-inning setup man? To answer that question, it helps to look at this past offseason’s free agent class.

There’s no question that top-tier starting pitchers get paid more than the top-tier relievers. No reliever, for example, got anywhere near the six-year, $126 million deal that the Cubs gave Yu Darvish, or even the $75 million over three years that the Phillies gave to Jake Arrieta. Things get a bit more interesting, however, as you move further down the food chain.

Other than Darvish and Arrieta, only seven free-agent starting pitchers got multi-year deals in the offseason. Contrast that with the market for relievers, in which 15 signed multi-year deals as setup men. (Wade Davis was the only established, bona fide closer to hit free agency, and he signed a huge three-year, $52 million contract with the Rockies.)

Aside from Darvish and Arrieta, only five starters—Alex Cobb, Tyler Chatwood, Jaime Garcia, C.C. Sabathia, and Lance Lynn—signed for more than $10 million per year, compared to two relievers—Brandon Morrow and Brandon Kintzler—other than Davis who did so. Twelve second-tier relievers, on the other hand, signed for at least $5 million a year, compared to just 10 second-tier starters who signed for comparable amounts. Here are those second-tier pitchers (excluding Mike Minor, who was a reliever with the Royals last year but who starts for the Rangers this year, and Michael Pineda, who started for the Yankees in 2017 but has been sidelined due to injury with the Twins in 2018):

Recent contracts Starters Years/AAV 2017 ERA 2017 ERA- Relievers Years/AAV 2017 ERA 2017 ERA- Starters Years/AAV 2017 ERA 2017 ERA- Relievers Years/AAV 2017 ERA 2017 ERA- Andrew Cashner 2/$8 3.40 74 Steve Cishek 2/$6.5 2.01 48 Lance Lynn 1/$12 3.43 81 Brandon Morrow 2/$10.5 2.06 50 C.C. Sabathia 1/$10 3.69 84 Anthony Swarzak 2/$7 2.33 53 Alex Cobb 4/$14.25 3.66 86 Tommy Hunter 2/$9 2.61 61 Tyler Chatwood 3/$12.67 4.69 94 Juan Nicasio 2/$8.5 2.61 61 Jason Vargas 2/$8 4.16 94 Yusmeiro Petit 2/$5 2.76 65 Jhoulys Chacin 2/$7.75 3.89 94 Addison Reed 2/$8.4 2.84 66 Jaime Garcia 1/$10 4.41 102 Brandon Kintzler 1/$10 3.03 68 Jake McGee 3/$9 3.61 72 Pat Neshek 2/$8.15 3.06 75 Bryan Shaw 3/$9 3.52 79 Luke Gregerson 2/$5.5 4.57 108

As starters, Lugo and Gsellman posted higher adjusted ERAs than all eight of the starters here with the exception of Garcia, and would therefore be lucky to get offers matching any of these already modest contracts. As relievers, though, Lugo and Gsellman would fit comfortably among the 12 listed here, and would seem due for multi-year deals with AAVs close to $10 million.

There’s a very strong argument that the Mets would be well served by moving Lugo and Gsellman into the rotation. Even if both proved to be “only” league-average starters, that’s more than the Mets have been getting most nights from the back end of their rotation. But for Lugo and Gsellman, they may find more money and better job security in the future by devoting themselves to becoming full-time, lockdown relievers.

The Sergio Romo experiment in Tampa could be a sign that the distinction between starters and relievers will fade in the years to come. If it does, it’ll be fascinating to see how teams change the way they compensate pitchers—and if pitchers start to embrace a transition to the pen that they once would have considered a “demotion.”