DALLAS — Former Dallas Cowboys fullback Daryl Johnston has a message for Dak Prescott during his contract negotiations — winning comes at a price too.

"The [six] highest-paid quarterbacks in the NFL last year weren't in the playoffs. None of them," said Johnston, an NFL analyst on FOX who is also the director of player personnel for the XFL's Dallas Renegades.

Johnston is referencing Green Bay's Aaron Rodgers, Atlanta's Matt Ryan, Minnesota's Kirk Cousins, San Francisco's Jimmy Garoppolo, Detroit's Matthew Stafford and Oakland's Derek Carr. Those were the six highest-paid based on average salary in 2018, according to Spotrac.com.

New Orleans' Drew Brees is tied with Carr for the sixth-most, but Brees and the Saints reached the postsesason. Pittsburgh's Ben Roethlisberger and the New York Giants' Eli Manning are other big names with big contracts that didn't reach the postseason.

Johnston's point for Prescott is that he has to leave the Cowboys with enough salary cap space to negotiate other deals to keep a solid nucleus in tact, much like they did with linebacker Jaylon Smith earlier this week.

If not, the Cowboys could end up with a roster good enough to make the playoffs, but not win a Super Bowl.

"Drew Brees wanted to be the highest-paid quarterback in the NFL and you saw New Orleans drop because you can't pay your third corner," Johnston said. "You can't pay your third wide receiver. You can't pay the designated rusher. [Baltimore's Joe] Flacco did it. Eli did it ...

"If Dak can just get to a comfortable number where he looks at everything, I'm being paid well, it is a life-changing contract financially, but you know what? I'm with a great group of guys that has a shot at this for three or four more years. That's what it's about. It's about winning championships."

Prescott and his high-powered agents at Creative Artists Agency (CAA) likely won't heed that advice. Instead, they know the quarterback salaries are only going to go up in today's market and Prescott is in line for a significant payday.

It may not re-set the market at, say $40 million, but it isn't going to be viewed as "team-friendly" either.

Johnston knows this as well as anyone. To him, it's just that the highest-paid doesn't always translate into Super Bowl victories, which is the legacy every quarterback leaves behind.

"It's this weird position that's got a dynamic that doesn't exist anywhere else," Johnston said. "We're just paying more and more because we're so afraid of not having that starter, because we're not developing that starting quarterback, so that thing just escalates up.

"It's the fear of being caught without a quarterback."