Brett Favre can't estimate the number of concussions he suffered throughout his football career because the number is too high for him to grasp in the first place.

"When you have ringing of the ears, seeing stars, that is a concussion," the Hall of Fame quarterback said Thursday, according to Richard Ryman of USA TODAY. "If that is a concussion, I've had hundreds, probably thousands, throughout my career, which is frightening."

Favre, who played 20 seasons in the NFL, has spoken about the affects head trauma has had on him during retirement in the past. He noted Thursday his memory continues to decline, leaving him to ponder whether he has chronic traumatic encephalopathy (CTE) - a dreaded degenerative brain disease that can only be diagnosed after death.

"It has gotten a lot worse in regards to short-term (memory); simple words that would normally come out easy in a conversation, I will stammer," he said. "And look, I am 48 years old ... could it just be, as we all like to say, as we get a little bit older, I forgot my keys and they were in my hand. Or, 'Where are my glasses?' and they are on my head. I wonder if that is what it is, or do I have early stages of CTE - I don't know."

Additionally, with awareness on the rise over concussions and their potential long-term effects, Favre believes football should entail minimal contact for kids under the age of 16.

"The brain and just the skull itself, for (8-to-15-year-olds), and maybe even older, is not developed enough and they should not be playing tackle football," he said. "We should protect them, especially when there is no treatment solution out there."

Favre is one of four prominent retired athletes who've invested in a company working to develop a drug called Prevasol to treat concussions. Fellow Hall of Fame quarterback Kurt Warner is also in the group.