The Washington Post first reported the news.
The 28-year-old signed with the Redskins back in 2014 on a four-year, $16 million contract. He caught 47 passes for 588 yards and two touchdowns over two years in D.C. Roberts was also the team's primary return specialist in 2014.
Crowder's development last year also made the move possible. The former Duke wideout starred at the 2015 Senior Bowl before catching 59 passes for 604 yards and two touchdowns in his rookie season. He also factored in on punt returns.
Roberts caught 182 passes for 2,123 yards and 11 touchdowns over his first four seasons in Arizona. In a fairly uneven wide receiver market, Roberts should find a home quickly if he doesn't intend on waiting out the Redskins.