Williams and Malik Hairston - the guard-forward from Oregon whom the Spurs acquired in a swap of second-round picks with the Phoenix Suns on draft night in 2008 - waged a battle throughout training camp for a potential 15th spot on the roster.

Hairston appears to have won a spot unless the Spurs opt to keep fewer than 15.

"It's always difficult," Popovich said after breaking the bad news to Williams. "This is the most difficult, in the sense that we could have gone in a couple different directions. The players were that close down the stretch, but it doesn't matter if a guy has played well, or poorly. It's always difficult to do."

Popovich won't be surprised if Williams is signed by another NBA club before season's end, though he acknowledged that fewer teams are keeping a full complement because of the soft economy.

"Whoever we cut should be on an NBA team," he said, "and it's a tough year to find a job. There's going to be an injury, and if guys don't get signed now, they may be signed at some point. But there are going to be fewer payers with jobs, or so I'm told."

Williams likely had a sense that his odds of making the club were slim after Popovich held him out of the team's final two preseason games.

In five preseason games, the 6-foot-7 Williams, out of Arizona, averaged 14.2 points, 1.6 assists and 1.8 rebounds, in an average of 13.2 minutes.

It's good to be old: Spurs at least 33 years of age didn't have to practice Sunday, as Popovich gave Tim Duncan (33) the day off, along with Michael Finley (36), Theo Ratliff (36) and Antonio McDyess (35).

The team's youngest player, 20-year-old DeJuan Blair, also was held out of drills to give a bruised tailbone another day to heal.

Blair is expected to be back on the practice court this afternoon.