Updated

Blake Griffin has officially withdrawn from the Olympics and Anthony Davis has been added to the U.S. basketball team's roster.

Griffin needs surgery to repair torn cartilage in his left knee and joins a lengthy list of American stars that are sidelined this summer.

Davis replaced him in the Americans' 113-59 exhibition victory over the Dominican Republic on Thursday in Las Vegas, scoring nine points in the fourth quarter. The No. 1 overall draft pick couldn't be put on the 12-man roster for London until Griffin had withdrawn Friday.

"Blake worked extremely hard in our training camp and certainly would have been a valuable contributor," USA Basketball chairman Jerry Colangelo said in a statement. "This is another unfortunate injury, but we have to continue to move on and we're very fortunate to have Anthony Davis available. Anthony offers our team additional height and length, and this will be an incredible experience for him."

Davis sprained his ankle during a workout with the New Orleans Hornets and was unable to scrimmage when the Americans opened training camp last Friday, ruining any chance he had of making the original 12-man roster. But Colangelo, intrigued by Davis' skills, asked the 6-foot-10 forward to stick around with the select team of young players that was training against the national team, knowing he could be called upon as a replacement if there were another injury.

The college player of the year at national champion Kentucky last season brings rebounding and shot blocking to a team that has lost Griffin, Dwight Howard and Chris Bosh from its frontcourt.

"Whatever Coach K wants me to do I am going to do," Davis said. "I am going to look forward to the challenges, and I'm looking forward to going overseas and my first time out of the United States. I am looking forward to that and getting to mingle with some of the guys and getting to know them and their workout routines and how they get ready for each game. They are superstars and they are here for a reason, so I'll just try to emulate what they do."

Davis made a quick impression Thursday in his nine minutes on the floor, highlighted by a 3-pointer he hit while being fouled just in front of the U.S. bench.

Griffin hurt his knee during the playoffs and played through the pain before the Clippers were eliminated. He was playing well in camp and being counted on as an option at center before experiencing pain in the knee following practice Wednesday. He flew back to Los Angeles on Thursday and an MRI exam revealed the extent of the injury.

"I'm disappointed I can't be with the guys in London," Griffin said. "I want to wish them all the best in their pursuit of the gold medal."

Davis will become just the third player to suit up for the U.S. in the Olympics without playing in the pros since NBA players were first used in 1992, joining the Dream Team's Christian Laettner and former Connecticut center Emeka Okafor in 2004. He will be back on the court with the Americans when they have their first practice here Saturday.