11/18/2013 08:47 EST | Updated 01/23/2014 06:58 EST

Concussion expert says players in contact sports still fearful over jobs despite injury threat

MELBOURNE, Australia - A leading concussion expert from the United States says players in high-level contact sports still are often fearful of sitting out games after head injuries because they might lose their positions in the team.

Chris Nowinski, a Harvard graduate and former wrestler, is a co-director of the Center for the Study of Traumatic Encephalopathy at Boston University, otherwise known as the "Brain Bank," one of the leading research groups in the world on the effects concussions are having on athletes, highlighted by recent cases involving National Football League players.

Nowinski has been in Melbourne meeting with officials from the Australian Football League players association and the National Rugby League.

"There still has to be a culture change with the players, they need to take that time off," Nowinski said in an interview with The Associated Press on Tuesday.

"They still have that impression that their job or role might be at risk. And I'm still not sure that players anywhere, even now, appreciate or understand the risk they are exposing themselves to."

He said Australian officials and those in the United States have become more aware of rest and recovery needed after concussions and head injuries, but even the prominent lawsuits in the NFL haven't improved the situation as much as he'd like to see it.

"You would think so, particularly is a player is mishandled," Nowinski said of the threat of legal action against teams by their players over head injuries.

"There is no reason now why a player can't come back to the team and say he had permanent brain damage and it was because of lack of proper treatment by the team doctors."

One of those players seriously affected by head injuries is Shaun Valentine, a former rugby league player in Australia who retired in 2003 after suffering seven concussions in 18 months while playing for the North Queensland Cowboys.

Valentine, whose short-term memory is terrible, is one of nearly 200 athletes who have donated their brains to Nowinski's Boston centre for posthumous research. The only way to confirm Chronic Traumatic Encephalopathy (CTE) caused by concussions is by examining brains after death.

Nowinski said he met the 37-year Valentine for the first time over dinner on Monday night in Melbourne.

"It was good to see him, we had a lot in common as we both are now about 10 years out since we had our concussions," Nowinski said. "We talked about how we can make things better in the future.

"How he's feeling, his experience of having those concussions over such a short period," Nowinski added. "How that was allowed to happen, to me, is one of the worst cases I have ever come across."

Even worse, Nowinski says, is that no one from the National Rugby League where Valentine played has ever contacted him about his current medical condition.

"I think they could learn something from him," Nowinski said. "It's unfortunate. Shaun proved his toughness in coming back from serious injuries, and where did it get him? No one should ever have to go through what he did again."