Federal prosecutors recommended on Tuesday that David Wildstein, who has described himself as the mastermind of the so-called Bridgegate scandal, serve no prison time as a result of his testimony against his co-conspirators, which followed his guilty plea.

Mr. Wildstein, the last of the major figures to be caught up in a scandal that dealt a blow to the presidential ambitions of Gov. Chris Christie of New Jersey, is set to be sentenced in federal court in Newark on Wednesday.

In a sentencing memo released on Tuesday, prosecutors noted that Mr. Wildstein could serve 21 to 27 months in prison based on the charges but asked that his sentence be reduced to probation because his testimony “led directly to the indictment and convictions” of two of his accomplices.

Mr. Wildstein, an official at the Port Authority of New York and New Jersey who had been appointed by Mr. Christie, confessed to coming up with the scheme to close lanes near the George Washington Bridge in 2013 as payback to a New Jersey mayor who did not endorse Mr. Christie’s re-election bid.