New England Patriots defensive coordinator Terrell Williams has been diagnosed with prostate cancer after, head coach Mike Vrabel told reporters on Friday. Vrabel opened his press conference with a statement about Williams’ diagnosis, saying that he is ungergoing treatment.

“(He) is in the process of treatment, and meeting with specialists, and figuring out the best plan of attack to be able to attack this and heal it and fix it and allow him to get back to better health,” Vrabel said. “You know how much Terrell means to me personally and to the people on this football team.”

Per Vrabel, linebackers coach Zak Kuhr will continue calling defensive plays in Williams’ absence. Kuhr took over some of Williams’ duties earlier this month, when the defensive coordinator took a medical leave of absence.

This story will be updated.