Jon Gruden has found himself in the midst of a racial storm.

The Las Vegas Raiders coach used a what many believe is a racist slur in an email 10 years ago, according to a report by The Wall Street Journal.

The email by Gruden was sent to the president of the Washington Football Team in July 2011 as its players were in the midst of trying to resolve a lockout. In the email, Gruden wrote that NFL Players Association executive director DeMaurice Smith had “lips the size of Michelin tires.”

Gruden has denied that the comments were racist. He told ESPN that he routinely uses the term “rubber lips” to “refer to a guy I catch as lying … he can’t spit it out.”

“I’m ashamed I insulted De Smith,” Gruden told ESPN, adding, “I never had a racial thought when I used it. … I’m embarrassed by what’s out there. I certainly never meant for it to sound that bad.”

Gruden told ESPN that he has spoken with the Raiders owner Mark Davis about the comments and that the two will likely speak again about the sensitive matter. He also told ESPN that he didn’t know if he would face any discipline from Davis or the NFL. Both parties condemned Gruden’s comments in public news releases on Friday.

Gruden’s Raiders are currently 3-1. They host the Chicago Bears on Sunday at 1:05. Gruden, who met his future wife while a graduate assistant at Tennessee, has long been a fan favorite to coach the Vols on the multiple occasions they had an opening at head coach. However, there were no significant reports that Gruden was actually considering heading up the Volunteers when he worked for ESPN.