Both the team and Cassel had options to walk away from the deal, and the nine-year quarterback decided that the $3.7 million he was scheduled to make was not fair market value for a starting quarterback.
#Vikings QB Matt Cassel will void his contract for 2014 and become a free agent, per source. Was to make $3.7M, had until Friday to do it— Ian Rapoport (@RapSheet) February 5, 2014
In fact, when comparing across the league, several mid-level quarterbacks are set to earn more than Cassel, including Ryan Fitzpatrick ($4.125 million), Kyle Orton ($4.378 million) and Matt Moore ($5.5 million).
So while the initial news may have come across that Cassel wants out of Minnesota, it's more of an issue that he simply wants more money.
According to general manager Rick Spielman, via Brian Hall of Fox Sports North, the Vikings were not surprised by the move:
"You know, from a business standpoint, you knew that was going to come," Spielman said Saturday at the team's annual Arctic Blast, benefiting the Vikings Children's Fund. "Basically, Matt's done a great job for us. We've already been in contact with his agent. I talked to Matt two nights ago on the phone. So, technically he's a UFA now and I'm sure we'll be visiting with his agent down the road as we go."
Given the current landscape at quarterback, which only includes Christian Ponder under contract, the Vikings are in a desperate position heading into 2014. And Cassel knows it.
Despite the complete debacle that was played out last season in naming a starter week to week, Cassel led the Vikings in passing with 1,807 yards for 11 touchdowns and nine interceptions.
The team secured the No. 8 pick in this year's upcoming draft, based on Minnesota's final record of 5-10-1, which puts Spielman in a similar position to 2011, when he drafted Ponder No. 12 overall.
How the team approaches that pick is still completely up in the air.
Either the Vikings pull the trigger on the best available quarterback in the first round—someone like Blake Bortles or Derek Carr—or they wait for the second round and take a shot on a player like Jimmy Garoppolo or Zach Mettenberger.
Regardless of how that scenario plays out, Minnesota would have no guarantee that the player selected can jump under center to open the regular season.
This is where it becomes vital that the front office makes an aggressive move to re-sign Cassel.
If instead the Vikings decide to let Cassel walk, they're essentially rolling the dice with Ponder for another season and a rookie quarterback who may not be the best option to start on Day 1.
The best-case scenario for Minnesota would be to bring back Cassel at a slightly higher rate than he was scheduled to earn, ensuring the team can still target in-house free agents, as well as other options in the external market.
Ponder would clearly be a distraction in this scenario, and a trade for a late-round draft pick in 2014 would be a nice consolation for the quarterback bust.
The Vikings will be busy this offseason, as they already have been with the addition of new head coach Mike Zimmer and offensive coordinator Norv Turner. If either provide any counsel to Spielman, one thing should be certain.
Minnesota must re-sign Cassel, with Ponder on his way out.
Matthew Stensrud is a Featured Columnist for Bleacher Report. You can follow him on Twitter and Google+.