John Harris was the ex-governor's chief of staff. He's a former military man with a law degree, ran the city's Department of Aviation and was budget director under Mayor Daley before joining the Blagojevich team.
Shortly after his arrest in December, Harris began talking with federal agents about the now ex-governor, and he's expected to do the same from the witness stand when the trial comes.
"We anticipate Mr. Harris may be called as a witness against the governor and others and if he is called he will again provide truthful testimony concerning matters he has knowledge of," said Terry Ekl, Harris' attorney.
In court on Thursday morning, Harris entered a not guilty plea, but his attorney indicated that will likely change within the next month.
Harris is charged in a single count of the Blagojevich indictment. He is heard on at least 100 secret government recordings, and his testimony against his former boss will be an important part of the government's claim that the ex-governor tried to sell Barack Obama's Senate seat.
Long-time Blagojevich buddy and key fund-raiser, Chris Kelly also entered a not guilty plea on Thursday. This is the third time he's been indicted. He is not cooperating with the government.
Nor is William Cellini, the long-time political power-broker who is named in three counts of the Blago indictment. His attorney says Cellini shook hands with Blagojevich once at a political function - that's it.
"Cellini and Blagojevich don't know each other. Cellini is a Republican. Blagojevich is a Democrat. Cellini should not be named in this indictment and it was wrong for the government to do that," said Dan Webb, Cellini's attorney.
Webb is asking that Cellini's trial be severed from Blagojevich, and Harris' attorney began is remarks on Thursday with this.
"John Harris has not asked permission to go to Costa Rico and be in a reality show," said Ekl.