OAKLAND, Calif. -- Brandon Rush's season is over after two games.

The Golden State Warriors announced Saturday that an MRI exam on the team's top reserve revealed a torn anterior cruciate ligament in Rush's left knee. He will have season-ending surgery in the coming days. The typical rehabilitation time is at least nine months.

"He's not doing great. He's devastated as you can imagine," said Rush's agent, Mark Bartelstein. "It's a traumatic thing to go through for anybody. We're going to figure it out and work with the Warriors and come up with a great plan to get him back. But for the moment, it's devastating with surgery and rehab ahead of you."

All the good vibes entering Golden State's home opener fizzled in an instant.

Rush leaped in the air for a dunk when Zach Randolph fouled him from behind with 4:09 left in the first quarter of the Warriors' 104-94 loss to Memphis on Friday night. Rush landed awkwardly, and his knee bent badly as he tumbled to the court.

The small forward got up on one leg, waved his arms in the air, and shook off teammates who tried to help. Rush covered his face in agony and eventually limped to the locker room with the support of teammate Jeremy Tyler and trainers.

"His reaction kind of said everything," Warriors point guard Stephen Curry said after the game.

Memphis selected third-string center Andris Biedrins to shoot the free throws. The home fans booed Biedrins -- the former starter -- before he missed both.

Richard Jefferson and second-round pick Draymond Green will be expected to fill the void in Rush's absence. The Warriors could also use the disabled-player exception to sign or trade for a player who earns up to half of Rush's annual salary.

Rush signed an $8 million, two-year deal in July -- with a player option for the 2013-14 season -- after coming over in a trade from Indiana for Lou Amundson last year. The 27-year-old Rush appeared in 65 of 66 games, posting career highs by shooting 50 percent from the field and 79 percent on free throws.

The forward fit seamlessly into coach Mark Jackson's system and became one of the team's best perimeter defenders, especially late in games.

Rush averaged 9.8 points and 3.9 rebounds in 26 minutes per game last season. He shot 45.2 percent from 3-point range -- sixth-best in the NBA -- and was Golden State's best option off the bench.

"It's a tough time," Jackson said Saturday night before the Warriors played the Clippers in Los Angeles. "It's a blow for us, no question about it, because we lose our best perimeter defender. Some teams you probably don't have to address when something like this happens, but this is an extremely close-knit group, and you could tell they were affected as soon as it happened."

Rush was drafted No. 13 by Portland in 2008 after leading Kansas to the national championship. He was then traded to Indiana along with Jarrett Jack and Josh McRoberts for Jerryd Bayless and Ike Diogu.

Rush originally declared for the NBA draft in the 2007 season until he tore the anterior cruciate ligament in his right knee. He never signed with an agent and returned to school, playing for the Jayhawks again only six months after surgery.

Just as he did before, those around him believe he will make a full recovery.

"He's strong minded," Bartelstein said. "Right now it's hard. I have no doubt he'll do great."