Lawyer Stephen Tapson said his client, Nancy Garrido, will go to trial unless she gets a better plea deal.
"Unless some hitch develops, I'm 99 percent sure Phil will 'plead to the sheet' and possibly be sentenced at the same time if (the) judge has figured out the correct number of hundreds of years," Tapson said, explaining he learned of the development from discussions with a lawyer for Phillip Garrido and the prosecutor in the case.
Phillip Garrido's expected guilty pleas by could be part of a strategy to help in his wife's defense, according to Steven Clark, a San Francisco Bay area defense attorney and former prosecutor.
"He will testify on her behalf and essentially take as much of the fall as he can for her," said Clark, who is not directly involved in the case.
The Garridos are each charged with 18 felony counts including false imprisonment, rape and child pornography. Nancy Garrido has pleaded not guilty. Phillip Garrido, a convicted sex offender, has not yet entered a plea.
They're accused of kidnapping 11-year-old Dugard from outside her South Lake Tahoe home in 1991 and holding her and her two daughters fathered by Phillip Garrido captive until their 2009 arrest.
Dugard, now 30, has said through her spokesman that she would be willing to testify if the cases went to trial.
If convicted on all counts, the maximum sentence for Nancy Garrido would be 181 years to life, while Phillip Garrido could get 431 years to life, according to El Dorado County Deputy District Attorney James Clinchard.
The Associated Press contributed to this report.