Indications have mounted throughout this week that a plea deal was in the works.
Manafort has already been found guilty on 8 charges of bank and tax fraud in a separate trial.
The deal is expected to be announced in court Friday, three people familiar with the matter told ABC News.
Manafort's lawyers have been in talks with Mueller's team about a plea deal for at least the last few weeks.More news: Hurricane Florence: Carolinas brace for 'storm of lifetime'
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Manafort hasn't been sentenced since his Virginia verdict, but the prospect of that prison time and more punishment in the District of Columbia case may have prompted him and his lawyers to seek to avoid the second trial. But if he does testify, the government asked Jackson to bar the defense from questioning Gates about his cooperation with the ongoing investigation, noting that many aspects of the more than 20 meetings he's had with prosecutors don't relate to Manafort's case. In ruling against Manafort's request for a change of venue, Jackson said she could reconsider if they are unable to qualify enough jurors to proceed to jury selection in the case, scheduled to begin September 17. Donald (Don) John TrumpTrump Jr. says he's not anxious about going to jail due to Mueller probe GOP chairwoman accuses Scarborough of using 9/11 to "score political points" Trump Jr. tears into Scarborough over 9/11 op-ed: You owe 3,000 plus families an apology MORE was offered damaging information on Hillary ClintonHillary Diane Rodham ClintonKavanaugh explains "abortion-inducing drugs" remark amid backlash Sheldon Whitehouse coasts to victory in Rhode Island primary Left risks backlash in Kavanaugh fight MORE. Doing so could jeopardize his chances at a presidential pardon.
Manafort attorney Kevin Downing said Wednesday that his team wants to introduce evidence showing the rarity of FARA prosecutions and to argue that the prosecution was instigated by the special counsel's office because Manafort led the Trump campaign. The agreement was described as "tentative".
None of the charges against Manafort related to collusion with Russian Federation.
Manafort is a significant figure in several threads of the Russian Federation investigation.