Keenum signed a two-year, $36 million deal in free agency with the Broncos in March after a a breakout year for the Minnesota Vikings in 2017. He completed 62.3 percent of his throws for 3,890 yards, 18 touchdowns and 15 interceptions in 16 starts in 2018 for Denver.
The Broncos went 6-10 in his first season with the franchise. The Broncos agreed to trade for Flacco on Feb. 13.
"Elway called me that morning and we had a great conversation, which he didn't have to do, and I appreciated that," Keenum said. "I was definitely shocked, it was a surprise for us and I think probably for the first day or so that's kind of what it was. But for us, we're definitely disappointed, it's not something we wanted to happen. I know that everybody's doing their job and John feels like that was a chance for him to help the Broncos out."
The 31-year-old is set to count for $21 million against Denver's salary cap this season. If the Broncos cut Keenum, it saves the franchise $11 million, with $10 million dead money.
Sources told NFL Network that the Broncos plant to trade Keenum. He would likely be asked to take a pay cut if he remains with the team.
The Flacco trade does not become official until March 13, the start of the NFL's new league year.