DAVIE, Fla. -- Miami Dolphins wide receiver Chris Chambers had headaches Monday, still feeling the effects of a "significant'' concussion.

Chambers had to be helped from the field Sunday night after taking a vicious shot from Denver Broncos safety Kenoy Kennedy in the second quarter -- a helmet-to-helmet hit that NFL spokesman Greg Aiello said is being reviewed by the league.

Chambers, who leads the team with 23 catches, went up for a high pass from Jay Fiedler and was hit in mid-air by Kennedy, and the ball came free. Kennedy was flagged for a personal-foul penalty for the hit.

It's not the first time he's made that type of hit this season. Kennedy was fined $10,000 last week for a similar hit to San Diego fullback Fred McCrary, and also was fined $7,500 earlier this season for a hit on St. Louis receiver Isaac Bruce.

A letter from the NFL warned Kennedy that future incidents could lead to a suspension. Aiello said Kennedy's past would factor into any punishment.

"That's always a factor when reviewing a situation like this,'' Aiello said Monday.

Chambers, meanwhile, might not play Sunday against the Buffalo Bills. Team trainer Kevin O'Neill called his injury a "significant concussion.''

"The fortunate thing is that there was no broken bones or fractures or anything worse than a concussion,'' Dolphins coach Dave Wannstedt said. "Hopefully Chris will start feeling better and we'll take it day-to-day and see where he's at this week.''

Wannstedt said he expects the NFL to punish Kennedy.

"It's inexcusable,'' he said. "There's no place in this game for taking a shot at somebody and trying to hurt them. As physical and aggressive as this game is, I would like to think no player is out there trying to bring injury to another player.

"The league will do something about it. The flag was thrown and the guy was penalized. He's been penalized before. Action will be taken. We're confident of that.''