Luke Ridnour has been diagnosed with an avulsion fracture of his pelvic bone, an injury that will keep the rookie point guard from playing for the Sonics' summer-league team next week in Long Beach, Calif.

General manager Rick Sund said the injury is not serious and should not prevent Ridnour from playing this season.

Ridnour can practice when the team's summer training camp begins Monday, but under the provision that he sustain only light contact and not try moves that require quick muscle contraction, such as leaping toward the rim.

Ridnour suffered the injury in the month leading up to the NBA draft, but it was thought to be a strained abdominal muscle. No one knew it was a fracture until after Ridnour underwent a magnetic resonance imaging test earlier this week.

An avulsion fracture of the pelvis is generally caused by a quick muscle contraction that tears a small piece of bone from the top of the hipbone.

Ridnour's workout for the Sonics on June 17 was his last on-court performance before the June 26 draft. He was at the team's practice facility Wednesday, lifting weights.