In surprise, ex-Penn State standout John Urschel tells Baltimore Ravens that he's retiring

John Urschel, the former Penn State lineman who became known as the NFL’s mathematics genius, is leaving football.

In a surprising move, Urschel, 26, announced Thursday, July 27, that he is retiring from the Baltimore Ravens.

“This morning John Urschel informed me of his decision to retire from football,” Ravens coach John Harbaugh said in a statement. “We respect John and respect his decision. We appreciate his efforts over the past three years and wish him all the best in his future endeavors.”

Although Urschel hasn’t commented on his reason for retiring, team sources indicated to The Baltimore Sun that it was related to the release of a study this week on chronic traumatic encephalopathy, or CTE, a debilitating brain disease. The study published in the Journal of the American Medical Association showed the existence of CTE in the brains of 110 of 111 deceased former NFL players who donated their brains to research.

Urschel in 2015 suffered a concussion that caused him to miss two weeks of the preseason. After the concussion, Urschel said, his ability to do high-level math problems was temporarily affected. But as recently as January on an episode of HBO's "Real Sports with Bryant Gumbel," he said he wanted to continue to pursue two things he loved.

“I recognize that this is somewhat irrational,” Urschel said on the segment. “But I am doing it. It’s more important to me that I’m able to do the two things I love.”

He has written about player health and safety for The Players Tribune and, in 2013, discussed accepting concussion risks to play football.

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"I'm well aware that when we play football, sometimes we may get a concussion," Urschel said then. "I think it comes with the territory. We're all adults here, we're grown men, and we understand the risk we take playing football. This is a game I love and I will happily take that risk every time I go onto the football field."

Urschel, who played three seasons with the Ravens, held one of the most unique stories in the NFL. He completed two degrees in mathematics at Penn State, where he also worked as an instructor while being a two-year starter at guard.

Last year, Urschel began pursuing a PhD in applied mathematics at MIT. He has published several papers and co-authored a theorem with Penn State professor Ludmil Zikatanov.

A fifth-round draft pick in 2014, Urschel played guard and center for the Ravens. He played in 42 games, with 15 starts, and the Ravens considered him a contender for the starting job at center this season.

Urschel's retirement could lead the Ravens to be more aggressive in their pursuit of free-agent center Nick Mangold.

The Allentown Morning Call and Baltimore Sun contributed to this story.