OAKLAND, CALIF. ? Reggie Jackson might be best known as the brash slugger who clashed with George Steinbrenner and Billy Martin and forever became “Mr. October” with three World Series home runs at Yankee Stadium.

But Jackson rose to prominence in Oakland and had his biggest success with the Athletics, who finally will retire his No. 9 today — 11 years after New York gave him the honor by retiring his No. 44.

“It’s probably overdue, but the A’s didn’t have anything to do with that,” Jackson said this week. “That’s me. There were some bad feelings with one of the executives. We didn’t see eye to eye. I let it go.

“Here we are getting things on the right track. The A’s have always treated me as good as you can treat a guy,” he said.

The 58-year-old Jackson played his first nine seasons with the A’s and also finished his career in Oakland in 1987.

His Hall of Fame plaque, however, features an “NY” on his cap, and he now works for the Yankees as a special adviser.

Jackson admitted he was anxious for this weekend’s fanfare to be finished, though he was looking forward to thanking the fans.

“I don’t get out there in public too much,” he said. “I’m very weird about it almost. When you’re a player and get on the field, you’re in your own fraternity, on safe ground. When you get on the field, you’re almost protected, in your element.

“I’m almost looking forward to it being over so I don’t do anything wrong, don’t do anything the wrong way. So I can run from it and hide. When I had my number retired in New York, you’re embarrassed a little bit, whether you should be or shouldn’t be.”

Jackson made 14 All-Star games in his career, including six with the A’s. He earned AL MVP and World Series MVP honors in 1973, hitting .293 with 32 homers and 117 RBIs.

He won three World Series titles with the A’s and two with the Yankees, hitting 269 home runs with the A’s and 144 with the Yankees. Jackson, who also spent one season with Baltimore and five with the California Angels, finished his career with 563 homers — eighth on the all-time list.

Jackson becomes the third A’s player to have his number retired, joining Rollie Fingers and Catfish Hunter. Several of Jackson’s former teammates will be on hand for the ceremony before the A’s play the Kansas City Royals.

The A’s won consecutive World Series, from 1972-74, while Jackson played for the team.