John Clayton of ESPN mused this week on 1500-AM radio that the best the Vikings could hope to get in a trade for Adrian Peterson is a fourth-round draft pick.

This probably sounds crazy to a lot of fans, but it underscores just how much the value of draft picks, cheap talent and running backs (particularly those about to turn 30 like Peterson) has changed over the years. To illustrate some of those points, here's a brief look back at trades involving draft picks and significant players in Vikings history:

Fran Tarkenton, QB (twice)

The Vikings traded Tarkenton (then 27) to the Giants in 1967 and received two first-round picks and two second-round picks in return. They reacquired him in 1972 (age 32) for three players and two first-round picks. Both of those trades would be considered massive return hauls today.

Herschel Walker, RB

Sorry, this had to be done. The Vikings acquired Walker (then 27) from the Cowboys in the middle of the 1989 season for, among other things, three first-round picks and three second-round picks. For those who want the Vikings to swindle Dallas with a "Reverse Herschel" trade: Not a chance.

Warren Moon, QB

The Vikings traded a third-round pick and fourth-round pick to Houston in 1994 for Moon (then 37). Yes, draft pick return value for a veteran quarterback two decades ago was possibly greater than the current trade value for Peterson.

Randy Moss, WR (twice)

In 2005, the Vikings traded Moss (then 28) to Oakland for linebacker Napoleon Harris and a first-round pick (No. 7 overall). He was later reacquired by the Vikings in 2010 (age 33) along with a seventh-round pick in exchange for a third-round pick.

Daunte Culpepper, QB

The Vikings traded Culpepper (then 29) to the Dolphins in 2006 for a second-round pick. To repeat: A QB nearly the same age as Peterson, who was injured in the midst of a terrible 2005 season, fetched a second-round pick.

Jared Allen, DE

The Vikings got Allen (then 26) in a 2008 deal with Kansas City, sending the Chiefs a first-round pick and two third-rounders.

Percy Harvin, WR

The Vikings traded Harvin (about to turn 25 at the time) to Seattle in 2013 for three draft picks — a first, a third and a seventh.

You could argue Peterson is the best player in this group. But if a midround pick is really all he's worth in a potential trade, this much is clear: Running back value has diminished, draft picks are gold and if a Peterson deal is made, it won't be for value. It will be for a fresh start on both sides.

michael rand