"The value for a player like that at his age (24), that's really what it costs you," Garrett said Tuesday on 103.5 The Fan, via the Dallas Morning News. "It costs you a first-round pick. If we were to get him in the draft next spring, you would say, 'Boy, is there any receiver who is as good as a guy like Amari Cooper?' He's not 28, 29, 30. You're not paying for a guy for what he's done for the past six, seven, eight years for another team."
Cooper, who was the fourth overall pick of the 2015 NFL Draft, earned a pair of Pro Bowl selections in the first two seasons of his career before struggling in the last two. He has 48 catches for 680 yards and seven touchdowns in 2017 before making just 22 catches for 280 yards and a score in six games this season for the Raiders (1-5).
Cooper is set to play next season under a fifth-year option worth roughly $13.9 million.
"We feel like he's a very physically talented guy," Garrett said of the 6-foot-1, 210-pound Cooper. "He's big, he's fast, he's quick and explosive, he has play-making ability, he's a good route-runner, makes contested plays on the ball."
The Cowboys (3-4) have featured a wide-receiver-by-committee approach since parting ways with Dez Bryant in the offseason. Dallas drafted Michael Gallup in the third round and added veterans Tavon Austin, Allen Hurns and Deonte Thompson to a group that included Cole Beasley and Terrance Williams.
Brice Butler, who was signed Sept. 18, was released Monday to make room for Cooper on the roster.
Beasley has a team-leading 33 catches for 350 yards and two touchdowns for the Cowboys, who own the 29th-ranked passing game. No other wideout has more than 13 catches on the team.