What is Marcus Peters really worth in a trade?

With Chiefs cornerback Marcus Peters reportedly on the trading block, what can Kansas City ask for him in return? Is he worth a first-round pick?

If a painter sets the price of a piece of art at $100,000, but no one is willing to pay more than $20,000, what is the true value of the piece?

Just because an artist asks a certain price doesn’t mean it’s worth that price.

The market sets value. If that artist could get two buyers interested, perhaps that could be used as leverage to drive up the price.

This is exactly how player markets work in the NFL, and while negotiating a deal for a player involves much more than haggling with the artist — in this case the work of art is a human being which means he’s actually part of the process as well.

By pro football standards, Marcus Peters is a distressed masterpiece, one of the most valuable pieces in any gallery. But just like the painter, the Kansas City Chiefs can’t just ask for the moon and expect to get it.

Just because a team asks for a first-round pick for a player, doesn’t mean the player is worth such a pick.

What is Peters, a 25-year-old All-Pro cornerback in his prime and on his rookie deal truly worth?

The Patriots traded a low first-round pick for Brandin Cooks. Shouldn’t Peters be worth at least that?

In the modern league, however, every team needs at least two solid to above-average corners to be a good defense, and usually three. That means the position is valuable, but how valuable is any single corner?

One receiver can make an offense. Ask the Buccaneers with Mike Evans or the Giants with Odell Beckham.

But Marcus Peters, though not quite at his peak in 2017, only led the Chiefs to the 23rd-best passing defense adjusted for schedule according to Football Outsiders. They call this stat DVOA (defense-adjusted value over average).

What if the position itself is valuable because any single team needs a cadre or corners, thus reducing the value of any single corner?

We know one great receiver can make a passing offense. Or a great running back can make a run game, even an entire offense. Can corners do the same?

To explore, I took the Pro Football Focus grades, combined then with the Bleacher Report Top 1000 grades, and PFF’s passer rating against rankings to create an indexed list of the top corners in football last season.

The top 10 looked like this:

1. A.J. Bouye
2. Marshon Lattimore
3. Casey Hayward
4. Jalen Ramsey
5. Darius Slay
6. Jimmy Smith
7. William Jackson
8. Kendall Fuller
9. Tre’Davious White
10. Marcus Peters

Intuitively, this list looks right. On this list, in order, the defenses when 1st, 5th, 9th, 1st, 16th, 2nd, 17th, 6th, 12th, and 23rd.

Clearly, one great corner doesn’t guarantee anything when it comes to passing defense.

But something else sticks out when examining the data. There were 11 teams with a passing defense that created value for their team. Below is the ranking with the number of corners ranked in the top 50 of our cornerback index.

1. Jaguars (2)
2. Ravens (2)
3. Rams (2)
4. Vikings (2)
5. Saints (2)
6. Washington (2)
7. Eagles (2)
8. Steelers(1)
9. Chargers (2)
10. Panthers (1)
11. Cardinals (3)

The 12th, 13th and 14th best passing defenses — the Bills, Seahawks, and Bears– also had two corners on the list.

Denver, who ranked 15th against the pass, actually have three.

Evidence seems to be mounting that in order to become a good passing defense, a team must have at least two really good corners.

Does that mean any single corner’s value must be lower as a result?

Pro Football Focus created a formula to attempt to quantify every player’s value on the field. Without getting into the logistics of the math, only one corner made the top-50 in Approximate Value and just five made the top-100.

This fits with the theory that any single corner simply doesn’t impact the game in the way we often assume.

Based on that information, it’s hard to justify a team spending a first-round pick on a player like Peters if even the best players at the position aren’t as valuable as conventional wisdom suggests.

That’s not to say the position itself isn’t valuable. We essentially proved in order to be a good passing defense, a team must have not one but two good players at the position. That makes the position valuable, but also suggests one great player doesn’t change a team’s life in a vacuum.

Coincidentally, Peters proved that last season when the Chiefs slid down the stretch because the rest of the secondary was a mess.

But the Chiefs traded for Kendall Fuller in the Alex Smith deal, with Fuller making the top corners list. That gives Kansas City two top corners to slide into their defense.

Perhaps the cornerback position is one where there’s an exponential effect. In other words, one great corner is much less valuable on his own than he is with another very good player.

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That suggests Peters’ trade value, because of his relative value to his own team, would have been lower before the Fuller deal because Peters was worth less to the Chiefs.

That’s no longer the case.

Remember our painter. If the artist thinks the painting is worth $100,000 and no one is willing to pay it, they can keep the painting.

It’s worth $100,000 to them.