"It's conceivable that very little if anything will be redacted (deleted)," U.S. District Judge James B. Zagel told attorneys as they prepared for the June 3 start of the trial.
The Chicago Tribune, Chicago Sun-Times and The Associated Press asked Zagel to unseal the document which the government says contains previously undisclosed facts about the case. Defense attorneys have objected to making the document public, saying it will put forth a one-sided account of the case.
Blagojevich is charged with scheming to sell or trade President Obama's former U.S. Senate seat and using his powers as governor to pressure campaign contributors illegally for money.
His brother, businessman Robert Blagojevich, is accused of helping him as chairman of the Friends of Blagojevich campaign fund.
Both have pleaded not guilty and deny any wrongdoing.
Federal prosecutors filed the so-called Santiago proffer under seal on Monday, saying they were acting out of "an abundance of caution" lest the court decide that previously undisclosed information contained in the document could prejudice prospective jurors. But they made no effort at Friday's hearing to keep it under seal.
Addressing the issue of how much new information is in the proffer, Assistant U.S. Attorney Reid Schar told Zagel it "puts meat on the bones" but reveals no "episodic conduct" that has not thus far been reported.
Defense attorneys said making all or parts of the document public now could jeopardize the integrity of the jury pool, as the trial is due to start in less than two months.
"We all agree we don't want the case tried in the media," Blagojevich attorney Sheldon Sorosky told Zagel. After the hearing, Sorosky said he expected that the document, or at least large parts of it, would be made public.