11/24/2017 04:33 EST | Updated 11/24/2017 05:44 EST

CFL commissioner Ambrosie says not enough evidence to link concussions and CTE

OTTAWA — CFL commissioner Randy Ambrosie says there isn't enough scientific evidence linking football head injuries to brain disease.

Ambrosie says he is "looking at all the evidence together and the answer is we don't know" if there is a connection between concussions and chronic traumatic encephalopathy.

The NFL has conceded there is a link, but the CFL has not followed suit.

Former CFL commissioner Jeffrey Orridge drew widespread criticism during last year's Grey Cup when he denied the existence of a link.

The CFL is facing a $200-million class-action lawsuit over concussions and brain trauma.

The strongest scientific evidence says CTE can only be diagnosed by examining brains after death, although some researchers are experimenting with tests performed on the living.

Many scientists believe that repeated blows to the head increase risks for developing CTE, leading to progressive loss of normal brain matter and an abnormal buildup of a protein called tau. Combat veterans and athletes in rough contact sports like football and boxing are among those thought to be most at risk.

While he hasn't seen enough evidence to be convinced that concussions can lead to CTE, Ambrosie says he is committed to making the game "better and safer for our players."

Ambrosie made the comments at news conference today in advance of Sunday's Grey Cup.