“Being capable of thinking quantitatively — it’s the single most important thing,” says the former NFL lineman.

Jennifer Chu:

It’s been nearly two years since John Urschel retired from the NFL at the age of 26, trading a career as a professional football player at the height of his game for a chance at a PhD in mathematics at MIT. From the looks of it, he couldn’t be happier.

The former offensive lineman for the Baltimore Ravens is now a full-time graduate student who spends his days in Building 2, poring over academic papers and puzzling over problems in graph theory, machine learning, and numerical analysis.

In his new memoir, “Mind and Matter: A Life in Math and Football,” co-written with his wife, journalist and historian Louisa Thomas, Urschel writes about how he has balanced the messy, physically punishing world of football, with the elegant, cerebral field of mathematics.