With no sign of any plea negotiations in the offing, two aides to Mayor Martin J. Walsh accused of extorting a music festival on behalf of union labor will head to federal court today to try to postpone the Jan. 8 start of their trial.

Kenneth Brissette, Walsh’s $101,719-per-year director of tourism, sports and entertainment, and Timothy Sullivan, the newly re-elected mayor’s $122,088-per-year chief of staff for intergovernmental relations, are due to appear before U.S. District Court Magistrate Judge Judith G. Dein at 11:30 a.m. and answer to a second superseding indictment that landed last week.

The defense added to the mix Friday by notifying the court in a status report that, in light of the new indictment that changes the language but does not add to the existing extortion and conspiracy charges, it wants to put the trial off for at least one month in order to respond.

Federal prosecutors countered that if the trial is put off, the earliest all lawyers are free to reconvene is March 26. The joint status report makes no mention of the parties trying to resolve the case short of trial.

BostonHerald.com reported Thursday that the U.S. Attorney’s Office had made a key language change to the extortion and conspiracy charges that could put Brissette and Sullivan away for up to 20 years in an apparent bid to avoid a legal pitfall that may have cost them a highly publicized case against four Teamsters earlier this year.

Rather than charging that in 2014 the pair sought to force Crash Line Productions, organizer of the Boston Calling festival, to hire members of the International Alliance of Theatrical Stage Employees Local 11 “for imposed, unwanted, and unnecessary and superfluous services and wages,” the new indictment redefines the alleged extortion as “money to be paid as wages and employee benefits and as wages and employee benefits pursuant to a contract with IATSE Local 11 … by the wrongful use of fear of economic harm.”

Federal prosecutors earlier this year lost a case involving Boston Teamsters, thanks to a 1973 U.S. Supreme Court decision that forbids charging organized labor with Hobbs Act extortion if their tactics are in pursuit of a legitimate labor objective.

Prosecutors had then claimed the Teamsters sought “unwanted, unneeded and superfluous” truck driving jobs that already had been filled by nonunion help — the same language used in the original Boston Calling indictment.