NEW YORK (CNNMoney.com) - The government will not call former Enron accounting chief Richard Causey to testify against his former bosses when the prosecution begins its rebuttal to the defense next week, according to a report in The Wall Street Journal.

Causey, who pleaded guilty in late December to one count of securities fraud, was the wild card in the trial as both the defense and the prosecution held out the possibility of calling him as a witness since the Enron trial began in late January. Causey's plea agreement, which his attorneys insisted didn't require him to testify against Enron founder Kenneth Lay and former chief executive Jeffrey Skilling, pushed back the trial by two weeks.

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The defense team representing Lay and Skilling expect to wrap up their side of the case by Monday. And the prosecution Thursday informed the court that Causey would not be among the 10 witnesses the government will present as a rebuttal to defense witnesses next week, the Journal reported.

Closing arguments in the trial will begin May 15.

Combined, Lay and Skilling face almost three dozen charges of fraud and conspiracy and could serve 20 to 30 years in jail if convicted. Lay has the added burden of facing another trial for bank fraud once the jury begins deliberations.

Enron filed bankruptcy in December 2001, causing billions in losses for investors and costing thousands of employees their jobs.