Campbell, who is the Jaguars' union representative, told ESPN's Michael DiRocco and Jenna Laine that nearly all players he has spoken to are against a 17th game:
"When I talk to the guys, I don't think many people want to do it. Really, you talk to guys and I don't think anybody wants to do it. It's going to be very, very tough. I know the ownership's really hard on it. We're definitely talking, trying to figure out what we need to do, how we can make this thing work. It's going to be a process, but 17 [games], that's very tough."
The NFL and its owners are hoping to add another regular-season game because of the revenue that comes with it, and it figures to be one of the biggest talking points during collective bargaining agreement negotiations.
The CBA is set to expire at the conclusion of the 2020 season.
ESPN's Dan Graziano noted that some of the other issues that will factor prominently into discussions are the revenue split, the use of the franchise tag and the drug policy.
Baltimore Ravens guard Marshal Yanda and safety Earl Thomas were among the players who were not receptive to a 17th game when asked about it Saturday.
A few players attempted to offer a possible solution, including Tennessee Titans defensive tackle Jurrell Casey and Minnesota Vikings defensive end Danielle Hunter, who suggested shortened training camp and OTAs.
Meanwhile, Atlanta Falcons tight end Austin Hooper called for a second bye week if a 17th game is added.
A 17th regular-season game would likely eliminate one preseason contest from the schedule, but since most starters don't play in at least one of the preseason games anyway, their workload would still be increased.
Per DiRocco and Laine, other incentives that have been discussed to lessen the sting of a 17th game include paying players more money, expanding the game-day rosters, expanding the playoffs, guaranteeing contracts and providing players with more of the revenue split.