Ravens center and resident genius mathematician John Urschel is retiring from the NFL after three seasons.

Urschel, 26, participated in all the team's offseason camps, but did not report for the start of training camp Wednesday.

Urschel said he wants privacy at this time, but released a statement hours after informing Head Coach John Harbaugh of his decision Thursday morning:

"Thank you to everyone for the kind words today. It wasn't an easy decision, but I believe it was the right one for me. I'm extremely grateful to the Ravens, and blessed to have been able to play the game I love at the highest level. It is a great game. There are some games – like the playoff game at Pittsburgh – that I will never forget.

"I'm excited to start working on my doctorate in mathematics full time at MIT. I'm looking forward to the chance to take courses that are only offered in the fall semester, while spending time with my fiancé and preparing myself for the new challenges that come with fatherhood. We're expecting our first child in December."

Urschel has gained national acclaim for his unique combination of brain and football power.

He's currently a Ph.D. candidate in mathematics at Massachusetts Institute of Technology (MIT), where he gets straight-A's and has released multiple research papers.

Here is Urschel’s MIT biography, which further explains the work he's doing there, including spectral graph theory, numerical PDE's, matrix algebra, computational finance, mathematical physics and others. He currently has the fastest eigensolver for minimal Laplacian eigenvectors.

Urschel has previously written and talked about his internal dilemma about playing football – something his mother had never wanted for him.

In an article written for the Players' Tribune in 2015, entitled "Why I Still Play Football," Urschel starts the piece by saying "I envy Chris Borland." Borland retired at 24 years old due to concerns about long-term brain injury.

Urschel wrote that he objectively shouldn't play football because of his bright future in mathematics, and because his other passions (reading math, doing research and playing chess) are very inexpensive.

"I play because I love the game. I love hitting people," Urschel wrote then. "There's a rush you get when you go out on the field, lay everything on the line and physically dominate the player across from you. This is a feeling I'm (for lack of a better word) addicted to, and I'm hard-pressed to find anywhere else."

A fifth-round pick in 2014 out of Penn State, Urschel has suited up at guard and center for 42 games and started 15, including two playoff games in 2014. Mostly a backup, he's been a reliable spot starter when injuries have struck.

Urschel was in contention to be the team's starting center this year, along with Ryan Jensen and Matt Skura. The three players rotated reps with the first-team offense throughout the summer. Now the Ravens will either turn to Jensen or Skura or look elsewhere.