"At some point, he became the second-best corner here," Coach Tom Cable said of Johnson. "That facilitated the ability to make this decision."

Johnson has started the past three games after playing on special teams and as an extra defensive back in passing situations. Before joining the Raiders in 2007, Johnson played only one full season in the NFL with the St. Louis Rams in 2005. A seventh-round draft pick by Green Bay in 2003, he was limited to nine games on the Packers' active roster over two seasons because of injury and saw no playing time. After his stint with the Rams, he was out of the NFL in 2006.

"I put in five good, hard years," said Johnson, 29. "Now it's paying off."

Johnson, wanting to make sure he was prepared when his opportunity came, attended an off-season camp run by former NFL standout Deion Sanders in Dallas. Johnson learned the finer nuances of the cornerback position from Sanders, Chicago's Devin Hester, San Diego's Antonio Cromartie and Dallas' Adam Jones.

Sanders' camp is designed to teach cornerbacks proper technique, how to gain an edge over receivers and what to look for as a play unfolds.

Sanders passed on his wealth of knowledge free of charge, beginning with workout drills at 7 a.m. and culminating with one-on-one drills against college receivers in the afternoon.

"Oh, man, he helped with my technique and other little things," said Johnson, who emulates Sanders at practice and is called "Prime Time" by his teammates. "But the biggest thing I learned from him is that you can't let receivers see you're doing the same thing.

"When Deion played, he wanted receivers coming to the line wondering what he's going to do. Now I use a different technique every time. It has helped a great deal."

During Denver's 31-10 loss to the Raiders on Sunday, Broncos quarterback Jay Cutler felt as if he had no other option but to go after Johnson, given the presence of proven cornerback Nnamdi Asomugha on the other side. He targeted Johnson on 11 of 37 passes. None went Asomugha's way. Johnson allowed three completions for 19 yards. Johnson also intercepted a pass and returned it 65 yards for a touchdown, but a holding penalty on Johnson negated the play.

"We believe in him because he can run and isn't afraid to play guys up close," Asomugha said. "He's not afraid to get beat."

The Raiders' game Sunday against Kansas City sold out in advance of the league-mandated deadline and will be televised locally.

The Raiders placed receiver Javon Walker (ankle) on the injured-reserve list. He was hurt Nov. 9 against Carolina and underwent surgery five days later. Oakland signed guard Dylan Gandy to take Walker's place on the 53-man roster. Gandy, 26, started 14 games for Indianapolis in 2005-07 and was waived by Denver in October.

Center Jake Grove (calf) and linebacker Ricky Brown (groin) did not practice and are day to day, Cable said. Brown missed the past four games, Grove the past two.