John Urschel

Baltimore Ravens offensive lineman John Urschel, known as the NFL's smartest player, is retiring after three seasons. Urschel, who has also been pursuing a PhD in math at MIT, informed coaches of his decision Thursday, just two days after a new study showed an even stronger connection between a degenerative brain disease and playing in the NFL.

In 2015, Urschel wrote a column in The Players Tribune in which he tried to explain why he continued playing football, given the increased risk to damaging his brilliant mind:

"Objectively, I shouldn't. I have a bright career ahead of me in mathematics. Beyond that, I have the means to make a good living and provide for my family, without playing football. I have no desire to try to accumulate $10 million in the bank; I already have more money in my bank account than I know what to do with. I drive a used hatchback Nissan Versa and live on less than $25k a year. It's not because I'm frugal or trying to save for some big purchase, it's because the things I love the most in this world (reading math, doing research, playing chess) are very, very inexpensive."

By playing three seasons, Urschel is vested to receive an NFL pension.

Our friends at HBO Real Sports profiled him in January. Here's the full segment: