William Glasgow told the Chicago Tribune that in 30 years, he's "never had a case have a post-trial motion of this nature."
Peterson's new defense team charges the lead counsel at his homicide trial botched the case by calling a divorce attorney to testify.
Divorce attorney Harry Smith offered the bombshell testimony that Peterson's missing fourth wife, Stacy, told him her husband had confessed to killing his third wife, Kathleen Savio.
Savio was found dead in a bathtub in 2004 but her death was initially ruled an accidental drowning.
Peterson, a former suburban Bolingbrook police sergeant, was convicted of Savio's murder last year.
Five months later, a split between his lead defense attorneys is calling into question whether a new trial is warranted.
Steve Greenberg has blamed lead attorney Joel Brodsky for the loss and Brodsky has retaliated with a defamation suit against Greenberg and the Tribune Co., the Chicago Sun-Times reported.
Glasgow said the case is in uncharted waters but sentencing could begin as early as Wednesday.