A day after their first preseason game, the Eagles traded wide receiver Jordan Matthews and a 2018 third-round draft pick to the Buffalo Bills for cornerback Ronald Darby.
Matthews, a free agent after the season, has been the Eagles' most productive receiver the last three years, catching 225 passes for 2,673 yards and 19 touchdowns.
But with his impending free agency, the additions of Alshon Jeffery, Torrey Smith and Mack Hollins, and the more glaring need at cornerback, the Eagles decided to make a deal.
Darby, 23, was a second-round pick in 2015. In two seasons with Buffalo, he had 137 tackles and two interceptions.
Darby had an impressive rookie season, placing second to Chiefs cornerback Marcus Peters in Defensive Rookie of the Year voting.
Pro Football Focus graded Darby that year as the fifth-best rookie cornerback since 2006, behind only Casey Hayward, Tyrann Mathieu, Joe Haden and Desmond Trufant.
As Buffalo's No. 1 corner last season, Darby didn't have as much success. Quarterbacks had a 104.8 rating when targeting him. To put that in perspective, Jalen Mills had a 97.7 passer rating against and Leodis McKelvin was at 113.0.
Darby is under contract through the end of the 2018 season. He has a cap hit of $800,426 this season and just under $1.1 million next season.
In a separate move, the Bills traded wide receiver Sammy Watkins to the Los Angeles Rams for a second-round pick and cornerback E.J. Gaines.
With Matthews gone, Nelson Agholor is expected to man the slot for the Eagles.