It's slang, so you may not find this meaning listed in the dictionary, but sometimes the word freak is used to describe amazing athletic talent and ability.
Bleacher report, which is a U.S. sports news website, describes it like this:
Other players .. rely on freakish, raw athleticism to make their mark on the game and outperform their competition.
One sports columnist for CBS Sports claims he has used the term for at least a decade now, stating:
I've been compiling the annual Freaks List for almost a decade now. It's a top 10 that spotlights the top workout warriors or players who amaze their teammates and coaches with what they can do in the weight room, on the track or in some other "wow" aspect of athleticism.
Dan Hanzus wrote a column describes Calvin Johnson as a "ridiculously gifted pass-catcher" in a column entitled Calvin Johnson, Randy Moss athletic freaks, an article that contains this quote from a fellow NFL player:
Calvin might be slightly stronger. Moss might be slightly faster. They can go back and forth on the attributes, physically. They both have a high IQ for the game. Both (have) extremely strong hands. And they're freaks of nature.
It's not just American football players that get this label. NBA player James White got called a "freak" by a blogger last month. One of his former coaches was quoted:
I had a bunch of great players, but he is by far the most athletic kid I’ve ever coached. I mean, he’s a freak of nature as far as his athletic ability.
NBA player LeBron James and baseball slugger Albert Pujols have also been honored as "athletic freaks," in a column that reads:
Everyone knows that professional athletes are some of the most physically gifted humans on the planet. They can run and jump faster than the average person and have impeccable hand-eye coordination to boot. In addition to their natural ability they often spend hours training their bodies to reach its optimum performance, which can often take their games to the next level. With this in mind, here are the top freak athletes in the 3 major sports!
One other column listed wrestlers and track stars in compiling the 10 Biggest Athletic Freaks of All Time. One may agree or disagree with their list, but they did mention how they used the term:
The term “athletic freak” can be defined, not as their talents within their respective sport (although that does certainly help), but their raw talent in terms of physical giftedness and athletic ability in terms of strength, size, raw power, and agility.
(They didn't mention speed, but many of those on their list – Hershel Walker, Bo Jackson, Deion Sanders, Jim Thorpe, and decathlon champion Bryan Clay – were indeed freakishly fast athletes.)