The procedure was performed at Summitt Hospital in Oakland. Late Friday, the Raiders placed Buchanon on injured reserve.
Under the original prognosis, Buchanon was expected to miss eight weeks and be ready late in the campaign if the Raiders could make the playoffs. Team doctors said the wrist would have lost most of its strength by that time.
Coach Bill Callahan said the team had no choice.
"(The decision was made) solely and exclusively where his wrist was not going to be able to go," said Callahan. "He's going to need recovery time."
Buchanon was the team's No. 1 pick in the NFL draft out of reigning national champion Miami. He made two interceptions, taking one 81 yards for a touchdown against Buffalo, and also had an 11.9 yard average on punt returns.
That left the Raiders with only one uninjured starter in their defensive backfield -- veteran strong safety Rod Woodson.
"We've got six guys on the field at one time in some of our defenses and we didn't have six guys," Woodson said about the game-winning drive by San Diego. "We need some DBs."
The Chargers beat the Raiders, 27-21, in overtime.
The Raiders already have declared cornerback Charles Woodson for Sunday's game against Kansas City because he has not fully recovered from a dislocated shoulder.
"It's my decision," Woodson said. "I want to be out there, but I've got to play it smart. "I don't want to go out there if it's not as close to 100 percent as it can be, risk the possibility of hurting it even worse so I'm out for the whole season. If it's not ready to go, believe me, I'm not going to be out there."
With Buchanon done for the year, Oakland has to make more adjustments on punt returns. They had to place veteran Terry Kirby on injured reserve as well.
Kirby also was hurt in the San Diego game, which is why Buchanon was needed for punt returns.
Kirby, a 10-year veteran out of Virginia, has undergone surgery on his broken right leg.
He had reinvented himself as a special-teams player this season. He had scored three touchdowns, including one on a 79-yard punt return, has rushed 16 times for 51 yards, and caught 17 passes for 115 yards.