Don't blame Antawn Jamison if he hasn't slept. He has been operating on Christmas Eve for the past three days.

"It's like the first day of school," an excited Jamison said Monday night from his home in suburban Oakland, Calif. "Christmas all over again."

Being traded from a perennial playoff outsider to a championship contender can turn back the years. After five seasons with the Golden State Warriors, Jamison officially joined the Mavericks late Monday afternoon when the NBA office approved the nine-player deal that was made public Friday.

The Mavericks also add second-year guard Jiri Welsch, power forward Danny Fortson and veteran small forward Chris Mills. Jamison, the Mavs' new starting small forward, and Welsch are scheduled to arrive in Dallas today for a news conference.

"It's hard to put into words what this means to me," Jamison said. "To go from a situation when you win 25-30 games a year to having a chance to win a championship with the best owner in the league and one of the best coaches ever, it's unbelievable. I couldn't get any sleep at first.

"Plus, you've got All-Stars in Steve Nash and Dirk Nowitzki and Michael Finley. That's a pretty scary combination."

The Warriors receive point guards Nick Van Exel and Avery Johnson, center Evan Eschmeyer, forward Popeye Jones and guard Antoine Rigaudeau. However, Rigaudeau plans to forfeit the second year of his two-year contract, giving the Warriors immediate salary relief, and sign with a professional team in Spain.

The other eight players have 10 days to report and pass physicals with their new teams.

The Mavericks likely aren't done dealing. Mills, in the last year of a contract paying $6.6 million, has piqued the interest of a number of teams. With Van Exel gone, the Mavs are in the market for a backup point guard or another low-post player.