The Raiders traded former first-round pick Cooper to the Dallas Cowboys earlier this week, leaving a gaping hole in an already suspect wide receiver corps.
Oakland (1-5) is coming off a bye as it prepares to host the Indianapolis Colts on Sunday. It will be the team's first game without Cooper and starting running back Marshawn Lynch, who was placed on injured reserve.
Cooper had 22 catches for 280 yards and a touchdown through six games, so the Raiders will need someone to fill the void for a passing attack that has been too reliant on tight end Jared Cook and running back Jalen Washington, who rank 1-2 on the team in catches.
"Each game is different, this is another game here that we'll see who's got a hot hand throughout the course of the game," Oakland offensive coordinator Greg Olson told reporters Thursday. "That plays into it, who are the matchups on the outside. But again, we feel like we have a number of guys at different positions that can step up and take place."
One of the guys Olson and the Raiders would like to see step up is wide receiver Martavis Bryant, who already has had a bit of a turbulent tenure in the Bay Area since he was acquired from Pittsburgh in April.
Bryant, who missed the entire 2016 season while serving a one-year suspension for violating the league's policy on performance-enhancing drugs, struggled in training camp and was cut on the eve of the season
The Raiders re-signed Bryant following a season-opening loss and are hoping he can show some of the game-breaking skills he flashed while with the Pittsburgh Steelers. He has 14 catches for 220 yards this season.
"I think he's such an explosive player," Olson said of Bryant. "I think it will help him the more he's in the system, the more he's here and is able to be around and stay within one system. In time, I think that helps a player like Martavis Bryant, because he's got tremendous skills, tremendous size and speed and he's still really kind of learning the system."
As a rookie, Bryant had eight touchdowns on only 48 receptions, averaging a stunning 21.1 yards per catch. A fourth-round pick out of Clemson, Bryant continued to thrive in a part-time role in 2015 with 50 catches and six touchdowns.
After sitting out the 2016 season, the 6-foot-4, 210-pound Bryant returned last year to catch 50 passes for 603 yards and three touchdowns for the Steelers.
Gruden called Bryant a "superb talent" after making the initial decision to cut him in early September, but did not mention his name when discussing the options in the passing game going forward.
"You lose a really good player, everybody has to step up," Gruden said. "Jordy (Nelson) obviously is going to be playing multiple positions. I think you'll see more of Seth Roberts. I think (Brandon) LaFell is a good player. He's played at a high level. He's been in a Super Bowl. He knows how to play this offense. We'll lean on all our receivers and certainly our tight ends as well."