The San Francisco 49ers were given permission Tuesday to talk to Oakland Raiders offensive coordinator Hue Jackson about their head coach opening.

Raiders senior executive John Herrera confirmed the request that was first reported by ESPN.

"Al is happy for Hue," Herrera said. "He would never stop Hue Jackson from an opportunity to coach. He believes in diversity."

The Niners fired Mike Singletary with one week left in the season. Trent Baalke was promoted Tuesday night to general manager from his previous position as vice president of player personnel. He interviewed with team president Jed York for about two hours last Saturday.

Jackson oversaw a vast improvement of the Raiders offense in his first season in Oakland. The Raiders more than doubled last year's scoring output.

York had insisted last week he would conduct a national search for the GM position but instead promoted from within. The 49ers have been without a GM since Scot McCloughan's abrupt departure last March in what York called a "mutual parting."

York has said the new general manager will have sole choice on who he hires as the new coach. Singletary was fired with one game remaining in his second full season as coach. He was 18-22 since replacing Mike Nolan on an interim basis in October 2008. The Niners (6-10) have missed the playoffs for eight straight seasons.

San Francisco is also interested in formally talking to Stanford coach Jim Harbaugh, who led the Cardinal to a 12-1 season and a 40-12 victory Monday night in the Orange Bowl over Virginia Tech.

The Newark Star-Ledger also reported that the Niners requested permission to interview Giants defensive coordinator Perry Fewell. If Fewell or Jackson interviews, the team will have fulfilled the requirement under the Rooney Rule to talk to a minority candidate.

Jackson also could be a candidate for the head coaching job in Oakland after owner Al Davis decided not to exercise the option to retain Tom Cable. The Raiders informed Cable of their decision later Tuesday.

Davis brought Jackson in after last season to take over the play-calling duties from Cable. Led by a breakout season from running back Darren McFadden and big plays from rookie receiver Jacoby Ford, the Raiders finished sixth in the league in scoring with 410 points. That was the sixth-most points scored in a season in franchise history.