"Laveranues Coles spent only one minute, 16 seconds on the bench - nine minutes in real time - after being knocked woozy in the fourth quarter of Sunday's overtime loss to the Raiders. His quick return seemed to indicate everything was okay.

It's not okay.

Coles suffered a concussion, coach Eric Mangini acknowledged Thursday - the third head injury in the last 22 months for the Jets' fearless wide receiver. Mangini wouldn't rule him out for Sunday's game against the Chiefs at the Meadowlands, but Coles didn't practice for the second straight day and appears unlikely to play.

Safety Eric Smith also sustained a concussion in Oakland, Mangini confirmed. That makes two concussions in three weeks for Smith, whose helmet-to-helmet hit Sept.28 on Cardinals receiver Anquan Boldin resulted in a one-game suspension. Smith also is uncertain for Sunday.

This would seem to be a growing concern for Coles, who saw his close friend, Wayne Chrebet, retire prematurely because of at least six documented concussions. Chrebet has experienced post-concussion symptoms since retiring in 2005.

Coles refused to discuss the matter, claiming he'd be fined for conduct detrimental to the team if he did. Mangini forbids players from discussing injuries. In this case, two public-relations officials hovered near Coles as he met with reporters at his locker in Florham Park, N.J.

"Unless you're going to fork over some cash, don't ask me no more damn questions about it," Coles said. "Talk to Eric and talk to the doctors."

Mangini said the team's doctors will determine if Coles can play this week. Per team policy, the doctors aren't permitted to speak with the media.

Three concussions in a 22-month span is "definitely a cause for concern," said Robert Cantu, a Boston-area neurologist. "But there isn't a magic number that should preclude somebody from taking part in an athletic activity. All concussions are not equal."

Concerns over the long-term effects of concussions, which some doctors believe could lead to dementia, have made it a hot-button issue in the NFL."