Campbell had insisted he wasn't concerned about being benched in the middle of games after it had happened twice this season.
Campbell was pulled out of last week's loss to the Pittsburgh Steelers in the third quarter and replaced by Gradkowski. It followed the benching of Campbell in Week 2, when Gradkowski took over after halftime and led Oakland to a 16-14 win.
"We talk about a lot of things all the time [and] he is OK with where we're going and what we're doing," coach Tom Cable said Friday of Campell. "He understands it's the job. It comes with it."
Campbell was chosen the team's starter in the offseason shortly after being acquired in a trade from the Washington Redskins but has struggled most of the year. His 75.8 quarterback rating is 29th in the NFL and he's thrown only seven touchdowns, with six interceptions.
Information from The Associated Press was used in this report.