Police said a large amount of cash and some jewelry were taken from Walker, who suffered "a moderate concussion and significant injuries to his face."
Police Lt. Clinton Nichols said detectives are retracing Walker's activities in the hours before he was found injured Monday on a street off the Las Vegas Strip.
COWBOYS: Terrell Owens wasn't on the field for the start of Dallas' mandatory off-season minicamp, and the receiver might not be around the rest of the week.
Team officials said Owens missed the first workout while tending to a personal matter. Owens did, however, attend meetings before leaving the Valley Ranch facility.
BENGALS: Wide receiver Chad Johnson is scheduled to have arthroscopic surgery on both ankles today, according to ESPN.com. Johnson is expected to be ready for the start of training camp.
TITANS: The agent for All-Pro defensive tackle Albert Haynes-worth doesn't think a long-term deal with Tennessee will be reached before the July 15 deadline.
Agent Chad Speck wrote in an e-mail to reporters that there has been no significant movement from the Titans, and that he doesn't expect anything new.
SEAHAWKS: Linebacker Lofa Tatupu entered a plea of not guilty to charges of driving under the influence of alcohol. Tatupu appeared before Municipal Court Judge Michael J. Lambo who set a tentative court date for July 7.
Buccaneers: Reserve quarterback Chris Simms , a one-time starter who hasn't played in a regular season game since Sep-tember 2006, was a no-show for the start of the team's mandatory three-day minicamp.
PACKERS: It isn't exactly a contract holdout, but running back Ryan Grant sat out Tuesday morning's mandatory minicamp practice.
Grant, who had a breakout year last season, hopes to prod the Packers into giving him a long-term contract.
JETS: Jay Cross resigned as team president after eight years to accept a position as president of Related Hudson Yards.
Cross replaced Steve Gutman as team president in 2001, and his top priority was helping the Jets create a new stadium. After a plan to build a stadium on Manhattan's West Side fell through, the Jets agreed with the Giants on a co-ownership deal to create a $1.3 billion, 82,500-seat stadium that's scheduled to open in 2010.