Cousins will become a free agent on Wednesday and could end up becoming the NFL's highest-paid quarterback. The Redskins opted not to use a tag on him for a third straight season, or even to negotiate a possible long-term deal. Instead, they agreed to trade for Kansas City quarterback Alex Smith on Jan. 30.
But Cousins waited until Monday to post the letter on his blog, signaling one more step in his divorce from the Redskins. At the bottom of the letter, two other teams in addition to the Redskins had been tagged: the New York Jets and the Minnesota Vikings. Those are among the teams that are expected to heavily bid on him. An updated version of his blog post did not include those teams.
"Knowing I will not be putting on a Redskins jersey next season, it's hard to look back on all that's taken place and not be emotional," Cousins wrote.
He said he'd be forever grateful to former coach Mike Shanahan for drafting him, three rounds after they selected quarterback Robert Griffin III with the second overall pick.
"At the time many people saw his selection as foolish," Cousins said. "Time proved otherwise and taught me that there are no guarantees in this business -- if you work hard and learn from your mistakes, good things can happen. For the first time in 11 years I will participate in choosing where I play. Having said this, I would not trade the past decade for anything."
Cousins was named the starter in the summer of 2015, after Griffin suffered a head injury. He started every game over the next three seasons, helping the Redskins win the NFC East in 2015. In those three seasons, Cousins threw for a combined 13,176 yards and 81 touchdowns and 36 interceptions.
The Redskins used the franchise tag on him each of the last two seasons after no long-term deals could be reached.
In his letter, Cousins touched on the positive memories of playing in Washington. That included having his "car mobbed" by fans at 3 a.m. at Redskins Park when they returned home from the division-clinching win at Philadelphia. There was his "You like that!" comeback win over Tampa Bay in 2015 that led to this becoming his catchphrase, one that he used to help raise money for the International Justice Mission.
"No words will express the depth of my gratitude, but 'thank you' will have to do for now," Cousins wrote.
Cousins said that even though he'll play elsewhere, "you never fully leave your first NFL team, especially after six seasons."
"My family and I will always have a piece of Washington deep in our hearts," Cousins wrote. "I arrived as a single, 23-year-old from the Midwest -- with a lot to learn and prove. I now leave as a husband of four years to my wife, Julie, and a father to my son, Cooper -- but still with lots to learn and prove."
And he recalled several teammates and what he would miss, notably left tackle Trent Williams, tight end Jordan Reed and linebacker Ryan Kerrigan. Cousins also thanked the organization -- coach Jay Gruden, team president Bruce Allen and owner Dan Snyder.
"When Cooper someday asks: 'Hey Dad, what was it like playing for the Redskins?' I'll proudly tell him it was a dream come true," Cousins wrote. "Thanks for having me, Washington, and thanks for making me into the player I am today!"