On his second day of rehab, top NBA draft pick Greg Oden walked into a news conference on crutches late Thursday morning.

He has started swimming, and a machine gently bends his knee for six hours a day.

The 19-year-old is expected to be on crutches for six more weeks. Full recovery likely will take six to 12 months.

“As you can see, he’s on his crutches and we’re excited about that…what is really nice is that we’ve got a great kid here who cares about this organization and his character is already shining through," Blazers General Manager Kevin Pritchard said.

"We know he's going to come back stronger than ever…and we couldn’t be more happy with the way things are moving and progressing already,” Pritchard added.

Oden said his injured knee is numb but does not hurt. When asked by a reporter Thursday whether he is confident he will fully recover, the teen joked that although he looks old, he's got youth on his side.

"I really am 19-years-old and I have young bones, so I can recover from this," Oden said. “I’m confident about my return, so nobody should be worried.”

Except for a videotaped blog entry, it was the 7-footer's first public appearance since undergoing microfracture surgery on Sept. 13. He will miss the season, spending it in rehab instead.

"I just want everybody to know, I did not hurt my knee getting up off the couch this summer, and I didn't hurt my knee playing 'Dance Dance Revolution' and break dancing this summer," Oden joked. "That did not happen."

He said the cause of his injury remains a mystery. He took time off after the draft, and then started feeling pain when he resumed training. He did laughingly admit to having a "Dance Dance Revolution" interactive video game at his home.

Oden was in good spirits, although he said the full impact of missing the season probably won't hit him until Tuesday, when the Blazers start fall practice for the season.

"You know, it is a setback, but I'm excited to be able to scout the NBA for the whole year, and just know that next year when I come in I'm going to be 20 years old, I'm going to be very mature, and I'm going to be ready to play."

He even predicted he'd be better than he was before: "I'm hoping for a 40-inch vertical."

On Wednesday, a giant get well card for Oden arrived in Portland’s living room – Pioneer Courthouse Square. A throng of eager fans signed the card, wishing Oden a speedy recovery.

More: Share your get well wishes

Oden underwent knee surgery earlier this month. Soon after, the Blazers announced that he needed significant recuperation time and would not play during the 2008 season.

More: Oden out for the season

Oden was the hotly anticipated pick after the Blazers scored the number one selection for the 2007-2008 season.

He averaged 15.7 points and 9.6 rebounds last season as a freshman at Ohio State, despite being hampered by a wrist injury. He led the Buckeyes to the national championship game, scoring 25 points and grabbing 12 rebounds in the loss to Florida.

The regular-season opener is at San Antonio on Oct. 30.

Oden also said the Blazers, with guard Brandon Roy, last season's Rookie of the Year, and forward LaMarcus Aldridge, would be fine without him.

"You don't know how good these guys are going to be this year. I've played against LaMarcus Aldridge, and he kills me every time," he said. "If they want a basket, give him the ball."