Scott Peterson's (search) lawyers planned to launch his defense on Tuesday, but the judge delayed testimony until Oct. 18.

Reasons behind the abrupt change weren't disclosed, though it's not the first time testimony in the long, complicated double-murder case has been put on hold.

Judge Alfred A. Delucchi (search) told the jury the recess might only last until Friday, but he scheduled testimony to formally resume on Monday.

"I hate to tell you this ... but we've got some problems that have arisen here. Some legal issues have come up," Delucchi told jurors. "I'm going to have to continue the case."

It was not immediately clear what issues the judge was referring to. Before addressing the jurors, he met with lawyers in his chambers.

The latest schedule shift in the trial means closing is now set for Nov. 1, instructions to the jury should be handed down Nov. 2 and deliberations should begin Election Day, Tuesday, Nov. 3.

Earlier Tuesday, legal analysts were abuzz at the prospect of Peterson taking the stand.

FOX News learned that lead attorney Mark Geragos (search) was on the fence about getting testimony from Peterson, accused of killing his pregnant wife and unborn son. Sources told FOX there was a 50-50 chance that Geragos would call the former fertilizer salesman, jailed since his arrest in April 2003, to the stand.

Some law experts balked at the idea, considering Peterson's image as a compulsive liar who cheated on his wife — even as the couple planned for the birth of their first baby, a boy they were going to name Conner.

"The prevailing legal wisdom is that it would be insane for Scott to testify," said FOX News legal analyst Judge Andrew Napolitano. "He would not be a credible witness and it wouldn't be worth the damage ... to put him on the stand."

In fact, conventional wisdom says it could be the nail in the coffin for the defense, because it opens Peterson up to cross-examination about any aspect of his life from birth on, according to Napolitano. That's not the case with other witnesses, who can only be asked about the matter at hand, he said.

But others say the defense could still win by proving one single fact: that the nearly full-term fetus was born alive long after Laci Peterson (search) was reported missing. That would mean Peterson most likely couldn't have killed them, because police watched his every move in the weeks after Laci disappeared on Christmas Eve 2002.

Napolitano speculated that if the defense team can put a believable expert on the stand who backs Geragos' theory, "the whole government case (against Peterson) collapses."

That evidence about the age of the fetus could either set the 31-year-old Peterson free — or send him to his death. But given how decomposed the bodies were after months in the water, it's going to be extremely difficult to prove.

Authorities could not determine a cause or time of death for either victim, and prosecution experts also couldn't agree on how the fetus was separated from its mother's body. They also couldn't exactly pinpoint the age of the fetus.

In his opening statement more than four months ago, Geragos made a bold promise: Defense experts, he said, would testify the fetus was older than it would have been had it died on Dec. 24 when Laci disappeared. He also told jurors the umbilical cord was cut in such a way that it must have been removed from her body while still living.

Prosecutors claimed the fetus was expelled from Laci's decaying corpse after it was sunk in San Francisco Bay by her cheating husband.

Dr. Brian Peterson, who performed the autopsy on the fetus, testified there was no evidence Laci had given birth before her death. But later, appearing to contradict himself, he said the fetus appeared to be full term.

Geragos implied the fetus could have been physically removed from a tear in the top of Laci's uterus, from where Dr. Peterson said it was eventually expelled.

"I couldn't say yes or no," Dr. Peterson replied.

Alison Galloway, an anthropology professor at University of California, Santa Cruz, estimated the fetus' age to be between 33 and 38 weeks based on bone measurements. Laci Peterson was believed to be 33 weeks' pregnant when she disappeared.

Geragos noted how inexact her estimate was, given the state of decomposition.

"I hate to say mushy, but that was sort of the way it was and that doesn't allow you to get an accurate measurement," Galloway said of the fetus.

The experts' testimony left holes that defense attorneys hope to fill when they begin their case.

Prosecutors allege Peterson killed his pregnant wife on or around Christmas Eve, then dumped her into the bay. The bodies washed up about four months later, mere miles from where Peterson claims to have been fishing alone the day his wife vanished.

Defense lawyers claim someone else abducted Laci and possibly held her captive while police homed in on Peterson, then crudely cut the fetus from her belly before framing her husband after learning of his widely publicized alibi.

"If this baby was born alive, clearly Scott Peterson had nothing to do with this murder," Geragos told jurors.

If Geragos can convince the jury the fetus was indeed at or near full term when it died, jurors likely couldn't convict Peterson for the killings. Laci's due date was roughly six weeks after her disappearance.

"It's going to be a battle of the experts," said former prosecutor and trial observer Dean Johnson said. "It's the one fact they need to prove to win this case. Everything else becomes background."

"If he can put experts on that will give some sort of credibility to that theory, that's the ballgame," added Robert Talbot, a professor at the University of San Francisco School of Law. "The defense's best shot is to show the baby was born later because nobody can really show that it wasn't."

It will likely all come down to credibility — whose experts the jury believes and whether there is enough reasonable doubt to lean toward innocence.

But what is reasonable?

Webster's dictionary defines it as "fair, just, wise, sensible."

But one man's sensible is another man's ridiculous.

"Reasonable is the great code word in the law," Johnson said. "It's just a code word for 'do whatever makes sense.' It's supposed to be objective, but many times, it's subjective."

FOX News' Greta Van Susteren, Catherine Donaldson-Evans, Rita Cosby and The Associated Press contributed to this report.