Cable had previously insisted the job was Gradkowski's once he returned from a shoulder injury, but the coach hedged after the Campbell-led Raiders beat Kansas City 23-20 in overtime on Nov. 7.
"[Campbell's] earned the right to do that," Cable said. "Four out of [his] last five games are wins. Bruce will back him up and we'll move forward from there."
Players returned from the bye week to continue preparations for Sunday's game against the Steelers, a game that has taken on added significance with the Raiders' recent success.
Oakland takes a three-game winning streak into Heinz Field and will try to make it four in a row for the first time since a five-game streak late in the 2002 season.
"People are really going to start talking about us for playoff contention if we do that," safety Mike Mitchell said. "That's the most important game of the year. Everything that we've done up to this point is going to come down to what we do Sunday. We just want to keep all that momentum going."
The Raiders got more good news, too.
Gradkowski, tight end Zach Miller and wide receiver Louis Murphy are all cleared to practice this week. Gradkowski has been slow to heal from an injury to his throwing shoulder, Miller missed one game with a sore arch and Murphy sat out two games with a chest injury.
Additionally, Pro Bowl cornerback Nnamdi Asomugha (ankle) and defensive tackle John Henderson (foot) may be cleared later this week. That would be a boost for Oakland's defense, which is allowing an average of only 236 yards during the winning streak.
Information from The Associated Press contributed to this report.