David Peterson is making a compelling case for the Mets' bullpen, and Monday's outing against the Colorado Rockies only added to the intrigue.

Working in relief, the left-hander tossed four solid innings, allowing two earned runs while striking out six. It was another strong performance that has become a pattern: Peterson now boasts a sparkling 2.45 ERA in three relief appearances this season. Compare that to his 8.10 ERA in five starts, and the numbers paint a clear picture—at least for now.

Of course, every pitcher dreams of being a starter, and Peterson is no exception. The Mets value him in that role, and given the choice, he'd take the ball every fifth day. But as the old saying goes, the numbers don't lie. "That's how I expect myself to pitch and that's how I expect myself to attack hitters," Peterson said after Monday's win. "So that's why it is disappointing when it has gone the other way a couple of times this year. Great win today and one to build off of."

Interestingly, this isn't Peterson's first rodeo out of the bullpen. He's made 18 career relief appearances in the regular season, though none since 2023. (He did pitch primarily in relief during New York's 2024 postseason run.) And the sample size is telling: his career regular-season ERA as a reliever is a microscopic 2.41 over 33.2 innings. In the postseason? A still-impressive 3.14.

As a starter, the story is more mixed. Peterson sits at 34-34 with a 4.33 ERA. His best year came in 2024, when he posted a 2.93 ERA in 21 starts after beginning the season on the injured list. Last season, he made his first All-Star team behind a terrific first half, only to fade down the stretch while logging a career-high 168.2 innings.

Despite the stark split in performance, the Mets and manager Carlos Mendoza remain committed to Peterson as a starter. "It's easy [to think Peterson pitches better in relief] because of three outings now where he's been really, really good," Mendoza said. "But I keep saying it, he's a starter. He's very good when he's at his best, and we saw it."

For now, the 30-year-old is thriving in whatever role he's given—and giving the Mets a welcome dilemma as they look to maximize his value down the stretch.