Bellefonte, Pennsylvania (CNN) -- The defense team for Jerry Sandusky rested on Wednesday without the former assistant football coach taking the stand.
Defense attorney Joe Amendola had told reporters earlier to "stay tuned" to see whether the former Penn State University defensive coordinator would testify. It was thought his testimony could provide the opening that prosecutors needed to introduce new evidence against the former coach.
Sandusky, 68, has pleaded not guilty to 51 counts related to accusations of child sex abuse against 10 boys over a 15-year period.
After the defense rested, the prosecution said it had no further rebuttal witnesses, and the judge scheduled closing arguments to begin at 9 a.m. Thursday.
The prosecution had called its only rebuttal witness on Tuesday, to counter testimony that raised questions about Sandusky's mental health.
Dr. Elliot Atkins testified that he diagnosed Sandusky with histrionic personality disorder, a class of conditions called dramatic personality disorders, which are marked by unstable emotions and distorted self-images. But a second psychologist, prosecution witness Dr. John O'Brien, disputed those findings, saying that the "personality profile Mr. Sandusky exhibited was within normal limits."
Following closing arguments on Thursday, the jury is expected to retire to begin deliberations.
At least one trial observer had said there was good reason for the defense to call the former coach to the stand. Veteran criminal defense attorney Ron Kuby said Sandusky is facing a "tsunami of evidence against him," and suggested that his taking the stand may be a way to help his case.
"Just maybe he can convince one juror to hold out," Kuby told CNN before the defense rested. "A hung jury, right now, is a lot better than life without parole."
However, some court observers had said that if Sandusky were to testify, prosecutors could potentially submit as new evidence a TV interview the ex-coach had with NBC sportscaster Bob Costas.
In a portion of the interview that was not part of the original November 2011 broadcast, Sandusky told Costas that he "didn't go around seeking out every young person for sexual needs that I've helped." There are likely "many young people who would come forward and say that my methods and what I had done for them made a very positive impact on their life," Sandusky said.
On Wednesday, the defense called Dr. Jonathan Dranov, an acquaintance of former graduate assistant Mike McQueary, who testified that he saw Sandusky sexually assaulting a boy inside a university shower.
Dranov told jurors that McQueary told him he heard "sexual sounds" and saw the boy in the shower when an arm reached around him, but that he told him he did not actually see a sexual encounter. Sandusky then emerged from the shower area, he said.
That account is different from what McQueary testified. The former graduate assistant said he witnessed Sandusky pressing against the boy in the shower, and that it seemed obvious that he had been raping him.
Before Wednesday's testimony, one juror was dismissed and replaced on account of illness. Prosecutors wrapped up their case Monday after eight of the 10 alleged victims were called to the stand, among other witnesses.
On Tuesday, Sandusky's wife told jurors that she could remember at least six of her husband's accusers staying overnight at their house, and said she did not witness any sexual abuse.
Dottie Sandusky recalled that one of the accusers had once traveled with them to a bowl game in San Antonio, Texas, where she and her husband shared a hotel room with the boy.
Many of the accusers testified that they knew Dottie Sandusky, who is not accused of having witnessed the alleged abuse.
She testified that children would often sleep at the Sanduskys' house and that "we would give them a choice of where they wanted to sleep."
Her husband also was the one to put the children to bed, typically, she said. She told jurors that "he would go downstairs and tell them good night."
The final prosecution witness testified Monday that her son seemed to suffer from stomach ailments during the times he was visiting Sandusky and sometimes did not want to visit the former Penn State assistant's home.
But she said she didn't ask him about any possible abuse and still does not know what happened to him.
"I didn't really want to hear," she said, crying.
The defense then opened its case with a former Penn State coach who testified about Sandusky's stellar reputation in the community.
Richard Anderson said it was not uncommon for coaches and youths to use the shower at the same time, and that he had never seen anything inappropriate between Sandusky and a child.
The defense called five other witnesses who supported the view of Sandusky's good reputation in the community.
"A lot of people lied," Amendola had said in his opening statement.
Over four days, several prosecution witnesses testified that Sandusky forced them to engage in sexual acts with him in various places, including showers in the Penn State coaches' locker room, hotel rooms and the basement of his home.
One told jurors that Sandusky -- whom he met, like many of the accusers, through the Second Mile nonprofit for disadvantaged youths that the ex-coach founded -- had threatened him if he told others about the abuse.
Another said Sandusky warned he might send him home from a trip to Texas, where they'd gone to watch a Penn State bowl game.
The defense challenged the accusers' timetable, questioning whether Sandusky could have committed the crimes they claim he did when they say he did.
On Monday, prosecutors dropped one of the 52 counts against Sandusky because the statute he was charged with wasn't in effect on the date of the alleged incident.
The accuser said the incident occurred in 1995 or 1996, but the unlawful contact with a minor statute didn't apply until 1997.
CNN's Susan Candiotti, Dana Garrett, Laura Dolan and In Session's Michael Christian contributed to this report.