The National Football League offseason is supposed to be a time for players to relax, recover from the brutality of the prior season, and prepare for the next one.

Not for Baltimore Ravens player John Urschel. The 6’3”, 305-pound offensive lineman will begin a PhD in mathematics at the Massachusetts Institute of Technology this year. The Hulk-like math geek, who graduated from Penn State with a 4.0 grade point average, will study spectral graph theory, numerical linear algebra, and machine learning.

In 2015, Urschel played in the NFL playoffs for the Ravens while simultaneously (pdf) working on a paper on graph eigenfunctions. (What have you done lately?) The paper, entitled, “A Cascadic Multigrid Algorithm for Computing the Fielder Vector of Graph Laplacians,” is available online.

NFL teams typically hold team workouts and other organized team activities (often shorted to “OTAs”) during the spring months, before official training camp begins in July. It’s unclear if Urschel will have to miss any of those activities in order to focus on his doctorate.

Urschel, who started in seven of the Ravens’ 16 games this past season, signed a four-year, $2 million contract with the team in 2014—small, for NFL standards. Perhaps a PhD will increase his profile, if not his player value.

In an illuminating Q&A with a publication of the American Mathematical Society, Urschel told interviewer Stephen Miller, vice chair of the math department at Rutgers University, that he spends time on road trips reading math books and research papers, but is able to separate his two interests when he has to.

… [I]f I’m thinking about math on the football field, this is going to get me killed. So that’s just survival instinct. And when I’m doing math, it’s all encompassing and I’m 100 percent in it, and there’s really nothing else to think about when I’m doing math.

In March 2015, Urschel wrote in the Players Tribune—the athletes-only journal started by former New York Yankee Derek Jeter—about why he continues to play football, given the injury risks and his flourishing career in mathematics. “What my mother and a great majority of my friends, family, and fellow mathematicians don’t understand is that I’m not playing for the money,” he wrote. “I’m not playing for some social status associated with being an elite athlete.”

“I play because I love the game. I love hitting people.”

As is practically tradition for NFL players, Urschel was diagnosed with a concussion last year. But it was a bigger deal for him than for most—not only did it jeopardize his health and his playing time, but it risked his future off the field as a mathematician. Urschel vowed to continue math-ing.

Urschel is not the first, or even the largest, professional athlete to ever try for a doctoral degree. NBA legend Shaquille O’Neal, who stands at 7’1”, earned an EdD in education from Barry University in Florida in 2012.