Soccer has a concussion problem. So many in and around the game don’t yet realize, or opt for ignorance. But it does. And it might just have a CTE problem, too.

According to a report from the Telegraph, former British midfielder Rod Taylor, who died earlier this year after succumbing to Alzheimer’s, has been posthumously diagnosed with chronic traumatic encephalopathy. CTE is the neurodegenerative condition, commonly found in former NFL players, stemming from repeated brain trauma and linked with dementia.

Taylor’s case does not prove anything about the links, or about CTE, or about soccer. But it adds to a slowly growing list of evidence that the sport puts its participants at a heightened risk of neurocognitive disorders later in life.

What is CTE, and what causes it?

CTE is a disease that can only be diagnosed posthumously – after death. Its symptoms can include memory loss, mood changes, confusion, depression and dementia. They begin to appear years after multiple blows to the head – which football and soccer players, among other athletes, often suffer.

Crucially, “blows to the head” does not equate solely to “concussions.” Subconcussive blows – “mild brain trauma that does not result in the readily observable signs and symptoms of a concussion” – might also be factors.

There is no proof that playing football or soccer causes CTE. But there is the obvious logical stream, from concussive and subconcussive blows – linemen smashing helmets, a defender heading away a cross – to sports, to CTE.

In the most extensive study yet, Boston University neuropathologist Ann McKee examined the brains of 202 deceased American football players; 177 of them were diagnosed with CTE. Of the 111 NFL players in the sample, 110 had CTE.

As McKee told a congressional roundtable in 2016: “I unequivocally think there is a link between football and CTE.” Almost every other expert agrees. And it seems there is some sort of similar link in soccer.

What is the evidence of CTE in soccer players?

Soccer is way behind. FIFA and other governing bodies treat concussions and their potential long-term effects like the NFL treated those topics decades ago. But evidence is slowly piling up.

The first diagnosis of CTE in a former soccer player arrived in February 2014. BU researchers found it in Patrick Grange, an amateur and semi-pro American player who had died of ALS two years earlier at age 29.

The first high-profile case in England was that of famous striker Jeff Astle. Astle’s 2002 death had been ruled by a coroner at the time a “death by industrial disease” – or, as the Guardian wrote, “heading heavy, often rain-sodden, leather footballs also caused Astle’s death at the age of 59.” In 2014, further examination of his brain led to a CTE diagnosis.

Research has picked up since. Later that year, former Brazilian star Bellini was posthumously diagnosed. More recently, in 2016, CTE was found in a former center back “with no history of concussion.” In 2017, it was found in a former amateur player who had died of drug overdose at the age of 24. That same year, a study of six former players with dementia yielded four CTE diagnoses.

What have soccer authorities done, and what are they doing?

Again, none of this is proof. It’s a catalyst for more research. Many American experts are in the process of carrying out studies. In England, one funded by the Drake Foundation and other organizations has the cooperation of the players’ association (the PFA). The PFA and the Football Association are funding a separate study led by Dr. Willie Stewart, the neuropathologist who diagnosed both Astle and now Taylor.

The issue is that those governing bodies and others have turned a blind eye to the issue for years. Thousands of players will likely suffer as a result.

There is a common belief, given the nature of the sports, that the threat of concussion isn’t as prevalent or worrisome in soccer as it is in American football. But that’s not necessarily the case, given the murkiness surrounding the long-term effects of subconcussive blows. A 2013 study by neuroscientist Michael Lipton concluded that “heading is associated with … cognitive abnormalities.” Experts have only scratched the surface when it comes to links between soccer and CTE. There’s every chance this develops into a full-blown, NFL-esque crisis.

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Henry Bushnell covers global soccer for Yahoo Sports. Have a tip? Question? Comment? Email him at henrydbushnell@gmail.com, or follow him on Twitter @HenryBushnell, and on Facebook.