Thomas played every snap in Miami's loss last week to Dallas but
said he felt "a little lightheaded" in the locker room after the
game, coach Cam Cameron said. Thomas complained of a migraine
Wednesday and missed practice, which led to the tests.
Thomas has fought migraine and concussion problems in the past
but has missed only 13 games in a 12-year career. A decision on
whether he can play this week is likely by Friday, Cameron said.
"In a lot of cases, the player wants to play," the coach said.
"Sometimes you've just got to take a deep breath, and sometimes
it's tough. You know what it means to lose a player like Zach
Thomas. But there is a lot bigger picture out there that you are
Thomas, a seven-time Pro Bowl player, had 10 tackles against the
Cowboys. Teammate Joey Porter said Thomas displayed no symptoms
during the game, other than repeatedly wanting a new mouthpiece.
"When you have a concussion or something, a new mouthpiece
always fits tighter and you get a better grip on it," Porter said.
"He had a mouthpiece, but he just wanted another one. A brand new
one is harder. The old one, you tend to chew on it, and you wear it
out a little bit."