Peterson was invited to the Mets' big-league camp Thursday.
Peterson still hasn't reached Double-A, so he isn't a real candidate to make the team's Opening Day roster. The 23-year-old made 22 starts between Low-A Columbia and High-A St. Lucie in 2018, posting a combined 3.16 ERA, 1.17 WHIP and 115:30 K:BB across 128 innings.