While the 2018 season was primarily filled with negative developments for the Met bullpen, a few bright spots emerged along the way. One such bright spot, was the emergence of Seth Lugo as an extremely useful arm out of the both the bullpen and the rotation.
Originally drafted by the Mets in the thirty-fourth round of the 2011 MLB draft, Lugo made his major league debut in 2016, and along with Robert Gsellman, helped pitch the Mets into a Wild Card spot after injuries ended the seasons of Jacob deGrom, Steven Matz, and Matt Harvey prematurely. The Mets primarily used Lugo as a reliever after his call-up to the 25 man roster in early July. Lugo thrived in this role, posting a 2.65 ERA and 2.68 FIP with 16 strikeouts and only 6 walks in 17.0 innings pitched in relief. After a series of injuries to members of the starting rotation, Lugo was moved from the bullpen to the starting rotation where he generally pitched pretty well, making his first start on August 19, against the San Francisco Giants. Lugo ended up making 8 starts for the 2016 Mets during August and September, posting a 2.68 ERA in 47 innings pitched as a starter, albeit with a 4.93 FIP that was almost two and a half runs higher than his otherwise stellar ERA. While Lugo’s performance as a starter was still pretty solid, he did see some significant decline in his strikeout rate after the move from the bullpen to the rotation, falling from 8.47 strikeouts per nine innings as a reliever to 5.55 strikeouts per nine innings as a starter. In addition to helping pitch the Mets into a playoff spot, Lugo also set a Statcast record for highest spin rate on a curveball when he unleashed a hook that registered 3485 RPM that got Anthony Rizzo to swing and miss despite the pitch hitting him in the foot. He averaged 3318 RPM on the pitch during his rookie season, which was the best average curveball spin rate in baseball in 2016.
After pitching for Team Puerto Rico during the World Baseball Classic before the 2017 season, and eventually taking over as the team’s ace, Lugo ended up landing on the disabled list with a partially torn UCL to start the 2017 season. He ended up not needing Tommy John surgery to repair the ligament, choosing to rest and rehab his balky elbow instead, and eventually returned to the Mets rotation in early June. He stayed in the rotation for basically the rest of the season, throwing 101.1 innings and making 18 starts for the Mets from June through the end of the season. The results were generally mixed for Lugo as a starter, as he posted a 4.71 ERA and 3.95 FIP with 1.6 fWAR. While his run prevention numbers left something to be desired, Lugo increased his strikeout rate from 17.3% during his rookie season to 19.5% during 2017, and decreased his walk rate from 8.1% to 5.7%.
After seeing his injury shortened 2017, and agreeing to terms with Jason Vargas to be the team’s fifth starter, the Mets decided to move Lugo back to the bullpen to start 2018. The decision would prove to be a wise one, at least with regards to maximizing Lugo’s on-field performance. Lugo thrived out of the bullpen almost immediately for the Mets in 2018, emerging - again alongside Gsellman - as a sort of multi-inning fireman type reliever who could be brought in to the game to get out of a tough jam and stay in for an inning or two if needed. Always a pitcher who picks up a little extra velocity and bite on his pitches in short bursts, Lugo was able focus on leaning harder on the pitch that got him to the big leagues: his curveball. This increase in curveball usage helped Lugo dominate National League hitters for the first two months of the season, posting a 2.21 ERA and 3.11 FIP with a 4.11 Strikeout-to-walk ratio in 38.2 innings pitched between April and May. He struck out 25.5% of the hitters he faced during the first two months of the season, a number well above the 18.7% career strikeout rate he posted in the two seasons prior to the switch to the bullpen.
Starting pitching injuries led the way for the Mets to slot Lugo back into the rotation from the end of May through the end of June, and Lugo was generally pretty good, if not quite as good as he was the two months prior. From his first start of the season on May 31 to the last start of his season on June 25 - a span of 5 starts and one three inning relief appearance, Lugo put up a 3.45 ERA and 3.62 FIP and struck out 29 hitters against 6 walks in 26.0 innings. Lugo moved back to the bullpen for the rest of the season and picked up where he left off, posting a 2.78 ERA and 2.60 FIP in the second half. After a full season of being used as something between a spot starter and a multi-inning reliever, Lugo contributed 101.1 innings - the exact same total that he threw the previous season - with a 2.66 ERA, 3.17 FIP. His 1.6 fWAR in 2018 was the fourth best mark on the Met pitching staff, and the 0.3 fWAR mark he put up in 26 innings as a starter was the fifth best mark among the members of the Mets rotation. He also posted a 25.1% strikeout rate, which was the best full season total of his career by a substantial margin.
Seth Lugo, Disgusting Curveball. pic.twitter.com/3R6LX4uPEh— Rob Friedman (@PitchingNinja) March 4, 2019
One of the best curveballs in baseball: @seth_lugo wipes out Josh Ockimey. Statcast has measured Lugo’s curve at as high as a record 3,500 rotations per minute. Lugo also threw the 4-seamer, 2-seam, slider, and changeup today—key piece for Mets in 2019. pic.twitter.com/3mczilXUcM— Jacob Zweiback (@TheReelJZ) March 4, 2019
Coming off his stellar 2018, Seth Lugo is currently slated to return to the bullpen in 2019. The Mets have seemed pretty intent on using him in relief all offseason and it’s easy to see why, even if both arguments are relatively strong. He was significantly better at run prevention out of the bullpen last season, posting a 2.30 ERA and 2.97 FIP in 78.1 innings of relief, both significantly better than the 3.91 ERA and 3.86 FIP he posted in the 23.0 innings he threw in games he started. While he struck out more hitters as a starter in 2018, the sample size of Lugo as a starter was almost three times smaller than the sample size of Lugo the reliever. It’s also worth noting that Lugo didn’t tend to go particularly deep into games when he started, averaging a mere 4.6 innings per start.
Even keeping his superior performance as a reliever in mind, there’s something to be said about Lugo probably being one of the five best starters on the roster for this upcoming season, which would probably mean he should at least be in consideration for a rotation spot over incumbent fifth starter Jason Vargas. There’s a compelling argument to be made for both sides, and in a lot of ways the difference between a multi-inning reliever and a back-of-the-rotation starter is kind of arbitrary and negligible. There’s also always the very good chance Seth will get his wish and return to the rotation at some point, either by design or to cover for an injury to another starter as he did in June of last season. Both PECOTA and ZiPS project him to be used relatively similarly to how he was last season, with varying degrees of success. PECOTA projects Lugo to throw 90 innings between the bullpen and rotation with a 3.75 ERA and 4.17 DRA and exactly 9.0 strikeouts per nine innings ratio, while ZiPS more conservatively projects him to throw 104.7 innings between the rotation and bullpen with a 4.30 ERA and 4.40 FIP and a lower 8.17 strikeouts per nine innings ratio. Regardless of the role he ultimately ends up in, Seth Lugo projects to be an important part of the Mets pitching staff, and another successful season from him would go a long way towards another successful season for the Mets.