The wide receiver returned to team headquarters Thursday on crutches and with a protective boot on his left foot. He had a simple message and a somber look on his face: "I'm done for the season."

Seriously?

"Yeah," Walker said.

And with that, one of the most criticized free-agent acquisitions of 2008 exited the locker room.

The NFL Network reported Walker would have surgery today on a bone separated at the ankle.

Interim coach Tom Cable was not available for comment as Walker returned to the facility after he had met with the media. Cable said Wednesday Walker was still undergoing tests on his ankle.

"They've got to put some screws in (the ankle)," Walker said without disclosing the extent of the injury.

Walker was injured on a 14-yard reception in the first quarter of Sunday's 17-6 loss to the Carolina Panthers. He left the game but returned and was diagnosed with a sprained ankle.

The Raiders signed Walker to a six-year, $55 million contract with $16 million guaranteed after he was cut by Denver. The Raiders were criticized for signing Walker to the deal, which included an $11 million signing bonus, considering Walker had two knee surgeries in the previous three seasons. Walker's base salary this season is $1 million.

And cynics poured it on when Walker approached then-head coach Lane Kiffin a week into training camp and said he wanted to retire and return his bonus money.

This came after Walker was robbed and beaten in June in Las Vegas.

Raiders owner Al Davis convinced Walker to stick with the team even though Kiffin often criticized the wide receiver's conditioning and effort.

A hamstring injury kept Walker out of the lineup for the season opener. He played sparingly in the Raiders' second game before making his first two catches as a Raider in Week 3 at Buffalo.

Walker's best game as a Raider came in a 16-13 overtime win over the New York Jets on Oct. 19. Walker had five catches for 75 yards and a touchdown.

He finished the season with 15 catches for 196 yards and the one touchdown in eight games. He ranks second on the Raiders in catches and yards behind tight end Zach Miller. Besides the Jets game, Walker didn't have more than two catches in a game as the passing attack has been inconsistent.

Walker was the only wide receiver with a catch against the Panthers, and he has been the only wideout involved in the passing game lately.

Ashley Lelie and rookie Chaz Schilens will start at wide receiver, with Johnnie Lee Higgins, Todd Watkins and Ronald Curry backing them up. None has a catch in the last two games, and Watkins has no receptions this season.

Read Jason Jones' Raiders blog at www.sacbee.com/Raidersblog.