NEW YORK -- The final act of Seth Lugo’s season began late Friday night, when the Citi Field bullpen phone rang. Mets manager Mickey Callaway asked Lugo if he felt strong enough to pitch two final innings, then spend the rest of the season as a spectator.

“I was excited for it,” Lugo said afterward. “I like going multiple innings, so I feel like that was a proper way to end the season.”

Lugo completed those six outs the same way he has so often this season -- without incident. When he finished, he walked off the mound with 80 innings, a 2.70 ERA, six saves and a career-high 104 strikeouts on the back of his baseball card. Among National League relievers, only Milwaukee’s Josh Hader has struck out more batters.

“What an outstanding year,” Callaway said.

For Lugo, 2019 marked the first season he did not make a single start, pitching all 80 of his innings out of the bullpen. The Mets have made no secret of the fact that they prefer him as a reliever, despite Callaway’s statement that Lugo “is very capable in both roles.” And because the rotation stayed uncommonly healthy this year with the Mets’ top five pitchers (lumping Jason Vargas and his replacement, Marcus Stroman, together) starting 154 of 162 games, Lugo’s function never came into significant question.

One of those starters, Zack Wheeler, is likely to leave via free agency, creating an opening in the Mets’ starting rotation. But in the team’s perfect world, the Mets will find some other way to fill it while continuing to use Lugo in relief -- a fate that he accepts, even if it’s not his preferred choice.

“I do want to start, but pitching in relief is fun,” Lugo said. “Getting in saves, finishing a game, that’s a lot of fun, too. That’s kind of the way I’ve approached the last couple years is, ‘Yeah, starting’s fun, my No. 1 goal. But pitching in relief is fun, too.’ As long as I’m on the team, that makes me happy.”

There is no question that regardless of his role, Lugo will be a significant part of the team. A year and a half after being diagnosed with a partial tear of the UCL in his right elbow, Lugo ended the season feeling both healthy and strong. Over the years, he has served the Mets as a starter, long reliever, setup man and closer, subbing in the ninth inning this year because of Edwin Díaz’s struggles. If the Mets are shy to re-anoint Díaz as their closer at the start of next season, Lugo could enter 2020 in a similar role.

At this point, he’s proven valuable regardless of inning.

“Learning from last year, I think I really figured out how to stay healthy and how to be at my best on a regular basis,” Lugo said. “I’m pretty proud of what I accomplished.”