Apologizes For Racist Langauge in 2011 Email

Jon Gruden says he's sorry for sending an email back in 2011 that contained racist language ... saying the comment he wrote was "horrible."

The email, according to the Wall Street Journal, was sent to Washington Football Team exec Bruce Allen ... and it contained a nasty remark about NFL Players Association executive director DeMaurice Smith.

"Dumboriss Smith has lips the size of michellin tires," Gruden wrote, according to the report.

The email was sent at a time when the NFLPA and the NFL owners were feuding over the league's collective bargaining agreement.

Gruden, who at the time was a broadcaster for ESPN, told the WSJ he didn't "specifically recall writing the email" -- but he added he…