The case for and against including David Peterson on the Opening Day roster

New York Mets pitcher David Peterson enters a pivotal 2023 season uncertain of his role on the pitching staff, as the team turned over nearly half of their entire pitching roster this winter.

The Mets currently have six pitchers who are projected to make the Opening Day roster (per Fangraphs) who were previously not on the team, and Peterson's expectations have changed as a result, so what is the debate about putting him on the roster at the end of March?

NY Mets pitcher David Peterson is only one of four left-handed pitchers on the 40-man roster.

The Mets have lacked left-handed pitching over the past couple of seasons. In addition to Peterson, the Mets only have two other lefties projected to make the Opening Day roster (Jose Quintana and Brooks Raley), and another likely to start in Triple-A (Joey Lucchesi). The Mets had another lefty pitcher, Tayler Saucedo, on their 40-man roster, but he was designated for assignment on Tuesday to make room for the recently-signed Tommy Pham.

Only three teams logged fewer innings pitched from lefties than the Mets, and Peterson pitched mor than half of them, and Mets' lefties had the highest walk rate in the majors at 11.1 percent (much of that had to do with Joely Rodriguez) and ranked 19th with a 4.22 ERA. So David Peterson will be needed both as a starter and a long reliever. Peterson was surprisingly strong as a long reliever when called upon last season.

In a division that includes lefty sluggers like Matt Olson, Michael Harris II, Kyle Schwarber, Luis Arraez, and possibly Bryce Harper (we'll see about his Tommy John recovery), Peterson will be called upon to neutralize them.

Peterson can also serve as a sixth starter when needed.

NY Mets pitcher David Peterson wasn't as effective down the stretch last season and his walk rate has been an issue his entire career.

David Peterson had a case to stay in the Mets' rotation when Max Scherzer came off the injured lit in September until his last three starts in early September, where he gave up 11 earned runs in 9.1 innings pitched in three starts, including giving up five runs while only recording one out against the Cubs in September, as these performances were one of the reasons the Mets lost the division.

He wound up not making another start afterwards, as he was relegated to the bullpen for the remainder of the season, so lack of confidence in command could be an issue for Peterson when pitchers and catchers report to spring training in three weeks.

Another thing he must work on, especially if he is to be a reliever, is his command and walk rate. He issued walks to at least one of every ten batters in each of his first three seasons in the majors, and in that ill-fated start against the Cubs in September, he issued walks to his first three batters, all on full counts (and they all scored).