The findings might explain the behavior changes Freel’s family noticed during his lifetime, said Robert A. Stern, a professor of neurology and neurosurgery and co-founder of Boston University’s Center for the Study of Traumatic Encephalopathy. Freel's mother, Norma Vargas, told NBC News that toward the end he was so depressed, there were days he didn't want to get out of bed. He was 36 years old when he died Dec. 22, 2012.
"I think it brings closure to many unanswered questions," Vargas told NBC. "I can’t say I feel better... I feel kind of relieved but I do feel better for my granddaughters -- as adults I think we're able to cope better and understand."
While there have been occasional reports of severe concussions in baseball, the sport hasn’t been on anyone’s radar as a high risk for brain injury. The Freel case underscores the fact that concussions can be a problem even in sports where they occur less frequently, experts say.
“The brain doesn’t know what rattles it around,” said Dr. Robert Cantu, a professor of neurology and neurosurgery and co-director of the Boston center. “CTE has been written up in the world’s literature in individuals who have never set foot on the athletic field, but have experienced repeated brain trauma."
Freel’s diagnosis wasn’t a surprise to Cantu. “He was a baseball player who also played football at a young age and who suffered an unusual number of concussions and who was described by his mother as one of those people who ‘leapt into everything head first,’” Cantu said.
“Baseball is not a collision sport,” Stern said. “It’s a sport that can result in collisions and concussions and blows to the head. But so can a lot of other activities. Just because there is a risk of injury doesn’t mean people should stop playing.”
Let our news meet your inbox. The news and stories that matters, delivered weekday mornings.
The focus for parents of Little Leaguers should be on the concussions themselves, said Dr. Joseph Maroon, a professor of neurosurgery at the University of Pittsburgh Medical Center, Heindl Scholar in neuroscience and team neurosurgeon for the Pittsburgh Steelers.
“There should be concern about any type of head injury,” Maroon said. “These certainly do occur in baseball, but not with the frequency as they do in football, soccer, hockey, or even field hockey. We know that multiple blows to the head may lead to prolonged problems.”
Maroon and others worry that fear of concussions might prompt parents to pull their kids from all sports.
That may have already started happening in football.
Between 2010 and 2012 there was a 9.5 percent decline in the number of kids opting to play Pop Warner football, said Josh Pruce, a spokesperson for Pop Warner Little Scholars, Inc.
And at least part of that decline may be traced to the high rate of concussions in football, said Dr. Julian Bailes, chairman of the Pop Warner medical advisory board and chairman of the department of neurosurgery and co-director of the Neurological Institute NorthShore University HealthSystem.
“Football has borne the brunt of the attention,” Bailes said, “but concussions aren’t just a problem with football or boys’ sports. They happen in girls’ sports as well. Sports such as soccer and ice hockey and basketball also have their share of concussions.”
Though Freel’s CTE diagnosis might scare some parents, he had far more concussions than the typical baseball player, Stern cautioned. In fact, even before Freel started playing professional baseball, he’d already sustained more than four concussions, the first of which occurred at age 2.
"He did everything fearless. Anything that he did. Yes, I was aware of that, but to be honest with you, it was not a good thing," Vargas told NBC. "I said 'Ryan, you can prolong your career, make a lot more money if you play safer than you do.' And he said, 'Mom, I don’t know how to play any other way. If I don’t play this way no one will see me. People come to see me because I play this way.'"
The most important thing for parents to understand is that properly managed concussions are far less likely to create long-term problems, experts said.
Parents also need to know that some people are more vulnerable to long-term problems from any kind of brain injury, said Dr. Douglas Smith, a professor of neurosurgery and director of the Center for Brain Injury and Repair at the University of Pennsylvania Medical Center.
Among those with more severe brain injuries, only about a third end up with brain changes similar to CTE, Smith said. “That means that even with severe injury two thirds do not have these types of changes,” he added.
Besides, Maroon said, think about the alternatives.
“Everything is relative,” he explained. “If you look at the mortality data, about 1,500 kids die each year riding in cars and there are several hundred thousand injuries. Bicycles have a much higher death rate than football.”
If you want to protect your kids, learn everything you can about concussions, Bailes said.
“Parents should learn how they occur and what the symptoms are,” he added. “And they should realize that sometimes the symptoms are subtle. Parents, like coaches, have to know what to look for and that they should get their child evaluated if they think there might have been a concussion.”
Linda Carroll is a regular contributor to NBC News and co-author of the book "The Concussion Crisis: Anatomy of a Silent Epidemic."