Looking that way according to his agent:

“‘We are happy because the injury doesn’t concerned the cruciate ligaments,’ N’Diaye said. ‘We are now monitoring the evolution of his injury, and we continue to talk with NBA teams. But it is never easy to draft an injured player. No decision has been taken yet but this is more and more likely Kevin will wait until next year.’”

http://www.slamonline.com/online/nba/2010/06/seraphin-will-likely-wait-until-next-year/

He's expected to be out 2-3 weeks so I don't think its surprising. I thought maybe Presti had scouted him enough that he'd be fine with taking him in the 2nd round but seems likely that he'll pull out and re-enter the draft next season.

At the very least it cuts down the list of prospective players that the Thunder may take and trims down the big-man class some.