Greg Oden, the top pick in this year's NBA Draft by the Portland Trail Blazers, will probably miss the next regular season that begins next month, his new club announced Thursday.

According to the Trail Blazers' web site the exploratory arthroscopic surgery and micro fracture surgery performed Thursday on Oden's right knee revealed cartilage damage.

"He was found to have articular cartilage damage in his right knee. The area of injury was not large and we were able to treat it with micro fracture, which stimulates the growth of cartilage," said team physician Don Roberts, who performed the surgery.

The 19-year-old center is expected to be out of action for up to eight weeks. Full recovery time after such a surgery generally takes between 6 and 12 months for full recovery from micro fracture surgery. The earliest he could set foot on the basketball court again is March.

The Portland Trail Blazers expect the 7-footer, who led Ohio State to last season's US college final as a freshman, to help them build a respectable franchise. The Blazers finished last season with a 32-50 record, the sixth-worst in the NBA. They've missed the postseason the past four years.

The New York native had his tonsils removed two months ago and missed the US team's training camp and later games at the FIBA Americas Championship, where the Team USA qualified for the Beijing Olympics.

Oden also missed the start of his only season at Ohio State University while he was recovering from a surgery intervention meant to fix a torn ligament in his right wrist.

After the recovery he averaged 15.7 points, 9.6 rebounds and 3.3 blocked shots, helping the Buckeyes reach college basketball's championship game for the first time in 45 years. In July signed a two-year contract with the Blazers which will earn him about $8.1 million.