"The general advice for a concussion is if in doubt, sit it out.
As the spotlight on concussions has grown, no doubt he's the one who has studied the effects, the trauma, the symptoms.
Jahvid Best, a first-round draft pick in 2010, did not play at all, and his future is in doubt because of concussion problems.
He left the field with concussion and could be in doubt for the Tigers round three NRL match against South Sydney on Sunday.
Williams was carried off on a stretcher after Wood's boot connected with his head as the flanker went for a loose ball, and the full-back is currently an injury doubt with suspected concussion.
The striker Ricky van Wolfswinkel, the club's record signing, is an absentee this weekend for the daunting trip to Manchester City with a troublesome foot injury, while Robert Snodgrass is also a major doubt after suffering concussion in the Capital One Cup defeat against Manchester United.
Aikman's career is now in doubt after his 10th concussion, and Irvin's career is over because of a neck injury, but Smith is still pounding away.
DOUBTS ABOUT BULGER St. Louis quarterback Marc Bulger was held out of practice yesterday, three days after sustaining a concussion, and his availability remained in doubt for Sunday's game against Atlanta.
"This year we have distributed 200,000 'Headcase' cards to the game giving advice on recognising concussion and stressing the 'if in doubt, sit it out' message.
ESPN says it will continue to report the concussion story, and I have no doubt that it will.
