Mike Tyson as Reggie Rhodes on “Law & Order: SVU.” (NBC/MICHAEL PARMELEE/NBC)

 About 5.2 million people watched Wednesday’s episode. That’s the long-running drama’s smallest audience on record for an original, regularly scheduled episode.

 Tyson played a death-row inmate who was a victim of childhood abuse and who had murdered one of his abusers in the episode, which also finished dead last in its timeslot among the major broadcast nets.

NBC doesn’t talk much about its overall audience, preferring to discuss18-49 year old viewers who are the currency of its prime-time ad sales. Here too the show suffered a record low for an original regularly scheduled episode.

Before it aired, about 7,000 people had signed a petition asking NBC to re-cast the role in the episode – a petition created by an ardent fan of the series who is a rape survivor and who said she felt betrayed by the stunt casting. Among those who signed the petition: “NCIS” star and abuse survivor Pauley Perrette.

Tyson was arrested in 1991 and charged with raping then-18-year-old Miss Black America pageant competitor Desiree Washington; he was convicted and served three years of a six-year prison sentence.

 Seen on Katie Couric’s syndicated talk show the day after his guest gig, Tyson continued to deny having committed the rape, as he had done in an interview with TV Guide magazine shortly before the episode aired.

 “I didn’t do anything to her,” Tyson told Couric, adding, “I took advantage of women, but never took advantage of her.”

 Couric’s mostly-female audience applauded. And Couric noted Tyson is still being “hounded” by the conviction, introducing the petition motif.

 “Everybody’s entitled to their opinion,” Tyson conceded of that effort to get his role re-cast.

 NBC ignored the petition request, but did move the episode which had originally been scheduled to air next week, learning that date put it on the eve of a global event in support of rape and abuse survivors.

 “Law & Order: SVU” wasn’t the only show to experience a ratings setback Wednesday night, though none on quite the same scale.

 “American Idol” and “Modern Family,” for instance, scored some of their smallest numbers in ages. And TV industry pundits spent a portion of Thursday navel gazing about the unusually low overall rate of people using TV for a night in which the landscape was awash in original programming.

 “Why do you think you were violent towards women, or tended to be abusive to women,” Katie asked Tyson during the pre-recorded interview.

 “No, no, no, no, no, no, no!” Tyson responded, making it seven in all.

 “In your past,” Katie hastened to add.

 “No, listen --  I was violent towards everybody,” he explained.