UFC officials issued the provisional suspension on Monday night after Penn, a former two-division champion, disclosed IV use that is banned by the U.S. Anti-Doping Agency.
"The UFC was notified today that the U.S. Anti-Doping Agency (USADA) informed BJ Penn of a potential Anti-Doping Policy violation," UFC said in a statement. "Penn disclosed the usage of a prohibited method -- the use of an IV in excess of 50 ML in a six-hour period -- during a March 25, out-of-competition sample collection."
UFC announced it is looking for another opponent for Miller on the UFC 199 card at Inglewood, Calif.
A former champion at 155 and 170 pounds, Penn (16-10-2) hasn't won a fight since he knocked out Matt Hughes in 21 seconds in a non-title bout at UFC 123 in November 2010. Since then he is 0-3-1, with losses to Frankie Edgar, Rory MacDonald and Nick Diaz. His bout against Miller at UFC 199 was scheduled to be fought at 145 pounds.
Arguably the greatest lightweight of all time, Penn had been preparing for his comeback at Jackson-Wink MMA in Albuquerque, New Mexico.
Information from ESPN's Brett Okamoto was used in this report.