George Papadopoulos is supposed to start his two-week prison sentence next week, but his lawyers are requesting a two-week delay pending the outcome of a separate case challenging the constitutionality of special counsel Robert Mueller’s appointment.

Papadopoulos, 31, was on President Trump’s foreign policy advisory team during the 2016 presidential election, and subsequently became part of Mueller's investigation into Russian election interference and possible collusion with the Trump campaign.

In October 2017, he pleaded guilty in Washington federal court to making false statements to FBI agents relating to contacts he had with Russian government agents while working for the Trump campaign.

In September of this year, U.S. District Court Judge Randolph Moss sentenced Papadopoulos to 14 days in prison, 12 months of supervised release, and 200 hours of community service.

Papadopoulos is scheduled to report to the Bureau of Prisons on Monday. But Papadopoulos’ legal team said in a filing earlier this month that outcome of the case brought against Mueller by Andrew Miller could “directly impact the validity of Mr. Papadopoulos’ prosecution of conviction.”

The judge is expected to rule on the motion from Papadopoulos’ lawyers to continue his bail, which was filed Nov. 16, before Monday. The motion filed Wednesday is a backup in case the judge does not do so.

The special counsel’s office is due to respond to respond to Papadopoulos' motion to continue his bail from earlier this month by 11 a.m. on Wednesday.

“Biggest regret? Pleading guilty,” Papadopoulos wrote in a Nov. 9 tweet that has since been deleted.

Miller, an associate of longtime Trump adviser Roger Stone, is challenging the constitutionality of Mueller’s position in the U.S. Court of Appeals for the D.C. Circuit. Miller is trying to block a grand jury subpoena from Mueller, and has refused to testify.

On Monday, Mueller’s team said the elevation of Matt Whitaker to acting attorney general does not effect the special counsel’s eligibility to lead the investigation into Russian election interference.

Miller’s attorney also said Monday that Whitaker replacing former Attorney General Jeff Sessions does not affect his argument that Mueller was named unlawfully by Deputy Attorney General Rod Rosenstein. The attorney said Rosenstein's appointment of Mueller in May 2017 gave him prosecutorial power that is too broad.