At some point, the New York Mets need to determine what they want David Peterson to be. Do they want more of the same, or do they want to have him develop to become what they thought they were getting when the organization made him their first round pick (20th overall) in the 2017 draft.

More than that, they may need to ask how having Peterson in the majors is helping anyone. His start in the series finale against the Arizona Diamondbacks indicated no one is.

After being staked to a 4-0 lead before he threw a pitch, Peterson imploded in the bottom of the first.

It was 2-0 before he recorded an out. After 35 pitches, there were only one out, and it was a tie game. At that point, Peterson needed to be relieved by Robert Gsellman.

Yes, Madison Bumgarner would knock in the go-ahead run, but Gsellman stepped up big time. He’d pitch 3.2 innings to help save the bullpen and allow the Mets to win the game.

This was Peterson’s 10th start of the season, and it was the fifth time he failed to pitch at least five innings. It was the sixth time he failed to go past five. It was also the third time he failed to go even four innings.

Taking it all into account, Peterson has been wholly unreliable. You don’t know what you’re getting from him start to start, and you don’t know when the implosion will invariably happen.

Before this start, the numbers were poor. He had a 4.63 FIP and a 79 ERA+. What’s scary is that’s with him getting some luck with a .290 BABIP.

Delving deeper, there are bigger problems. Looking at Baseball Savant, he doesn’t have much velocity or spin. Taking that into account, we probably shouldn’t be surprised he’s getting hit very hard.

This isn’t just this year. Yes, Peterson’s ERA and WHIP were better last year, but it was all an illusion. Peterson still had a 4.52 FIP, a poor K/BB, and he was getting hit hard. He was just extraordinarily lucky with a .233 BABIP.

Really, when you break this all down, Peterson wasn’t ready last year, and he shouldn’t have been pushed again this year. He needed more time to work on things, but the Mets short-sightedness interfered.

Now, we all know the counter-arguments. Carlos Carrasco and Noah Syndergaard aren’t close to returning. Thomas Szapucki probably isn’t ready. No one trusts or wants to trust Jerad Eickhoff or Corey Oswalt.

The excuses goes on and on. However, when having those discussions, the focus needs to boil down to what Peterson is.

There needs to be a realization Peterson doesn’t give the Mets what they need at least half the time. It’s probably less than that, and based on what we’ve seen lately, that may be an optimistic view of things.

No matter what you think of the plan beyond Peterson, we should be able to agree he’s not really ready for the majors. Therein lies the problem, and that’s why he should be sent down.

In the end, that’ll help him develop more than he can right now. That’s what the Mets need from Peterson. The 2021 innings can come from a minor affiliate. This is what will be best for him, and that means it’s what’ll be best for the Mets.