The prosecution, as part of its rebuttal case, will play a one-hour taped interview with the teenage boy conducted by the Santa Barbara Sheriff's Department in 2003, reports CBS News Correspondent Steve Futterman.
Judge Rodney S. Melville decided Thursday to permit jurors to see the July 2003 videotape.
In response, the defense threatened to shove aside the last 60 days of testimony and bring back the people at the heart of this case: the accuser, his mother, his lawyer and his therapist, reports CBS News Correspondent Vince Gonzales.
The case had been expected to go to the jury next week, but that became uncertain with the possibility of extensive new testimony.
"This certainly would extend the case if they do call who they say they will," said former prosecutor Susan Filan. "However, this may be defense bluff and posture."
Melville, however, turned down a prosecution request to show pictures of Jackson's genitals that were taken during a previous molestation investigation.
Jackson, 46, is charged with molesting a 13-year-old boy in February or March 2003, giving him wine and conspiring to hold his family captive to get them to rebut a documentary in which Jackson said he let children into his bed but nothing sexual happened.
On the 2003 tape the boy for the first time tells law enforcement officials that he was molested by Jackson.
The tape could hurt the defense.
"You don't want that to be the most recent memory in the minds of the jurors before they enter the deliberation room," former Santa Barbara prosecutor Craig Smith.
"Right now, the jurors are sitting on the edge of reasonable doubt. If he looks credible, this puts the case back on track for a conviction," said courtroom observer Filan.
Prosecutors contend a videotape of the boy's first police interview will show that his story has been consistent.
Defense attorney Robert Sanger argued the tape contains "prejudicial material" such as officers telling the boy: "You're really brave, we want you to do this."
Sanger also argued against the prosecution's request to show photos of Jackson's genitals, saying it would be "very shocking" and prejudicial to the jury.
"I actually talked to Michael after that photo session. He told me it was the most humiliating experience of his life," said Jackson biographer and CBS News Consultant J. Randy Taraborrelli.
After taking the photos, authorities had the boy involved in the case draw a picture of what he thought the genitalia looked like. Prosecutors claimed the picture showed a unique blemish.
The boy in the investigation and his family eventually received a multimillion-dollar settlement from Jackson and no criminal charges were filed.
"Michael always feared these photos would come back one day to haunt him, and they almost did," said Taraborrelli.
Arguing for use of the graphic pictures, Senior Deputy District Attorney Ron Zonen said the prosecution wanted to show jurors a child's description "of a unique feature of (Jackson's) anatomy."
Zonen said it would show that Jackson's relationships with boys were "not casual."
The judge refused to allow the pictures, saying the prejudicial effect of the photos would far outweigh any value.