Cousins, who will make $23.9 million this season, and the Redskins can't negotiate a long-term deal until the season ends by virtue of being unable to come to an agreement by Monday's deadline.
Shanahan was the offensive coordinator in Washington during Cousins' first two seasons in the league, and it's been reported that they have a strong connection.
Assuming something surprising doesn't happen, it's going to mean that Cousins will enter the 2018 National Football League offseason with the potential to still work out a long-term deal with the Redskins.
Cousins followed up a breakout 2,015 campaign by completing 67.0 percent of his passes for 4,917 yards with 25 touchdowns and 12 interceptions last season. Last year, he made $19.9 million under the tag.
ESPN's Adam Schefter reported on Sunday that Cousins was not expected to sign a long-term deal.
In 2016, Cousins finished with single-season team records in attempts, completions and passing yards and matched his team record for 300-yard passing games (seven).
The 28-year-old is heading into his third full season under center as Washington's starter since taking over for Robert Griffin III.
For comparison, Derek Carr's contract (worth $125 million over five seasons) includes just $40 million in guaranteed money, which is, um, a lot.
According to the Monday Morning Quarterback, there has been some doubt in the minds of a few Redskins front office members.
Cousins and his teammates will return to the field next week when training camp opens up at the Non Secours Washington Redskins Training Center in Richmond, Va. Other teams will have the right to go get him if they don't franchise him, and it's hard to imagine they would franchise him. The Redskins would then have one week to duplicate the offer he would receive elsewhere.
Cousins will now enter the 2017 season as the only QB in history to be franchised for two consecutive seasons. He's going to get multiple offers from teams desperate for quarterbacks, perhaps including the San Francisco 49ers, who have Kyle Shanahan at head coach. So in all, Cousins will have made almost $44 million in two years by accepting the relative lack of long-term stability that comes along with the franchise tag.
Right now, the 49ers have four quarterbacks on the roster with Brian Hoyer, Matt Barkley, and rookie C.J. Beathard being the most likely to make the 53-man roster. Research suggests the hit rate for a first-round quarterback hovers around 50-50.