In letters to the chairmen of the House and Senate Appropriations Subcommittees on Commerce, Justice, Science, and Related Agencies - with whom Sessions was originally scheduled to appear Tuesday - he wrote of the necessity to change his schedule following former FBI Director James Comey's hearing last week and an invitation to appear before the Senate Intelligence Committee.
Richard Shelby, Senate Appropriations Committee chair, Sessions cited public statements of some members that they would use their time with Sessions to ask him questions about the Russian Federation issue instead of the purported subject of discussion, the Department of Justice's FY 2018 budget.
Briefing congressional appropriators on the Justice Department's budget is a critical part of the attorney general's job.
Speaking to lawmakers later in closed session, sources said, Comey confirmed that he had been talking about a story that NBC News and other outlets had already reported - the existence of classified intelligence suggesting an undisclosed meeting between Sessions and the Russian ambassador to the U.S.in April 2016 at the Mayflower Hotel in Washington, D.C.
As for the timing of Sessions' recusal, Comey said the FBI expected the attorney general to take himself out of the matters under investigation weeks before he actually did.
It is unclear whether the upcoming intelligence committee hearing will be open or closed.
Instead of testifying publicly before the appropriations committees, where these matters could be discussed in the light of day, Sessions will appear before the Senate Intelligence Committee.
The attorney general cited his involvement in Trump's campaign for stepping away from the Russian Federation investigation in March.
Comey said Trump told Sessions and other administration officials to leave the room before Trump asked him in February to drop a probe into former National Security Adviser Michael Flynn's contacts with Russian Federation. If Comey is to be believed, Sessions has been under Federal Bureau of Investigation scrutiny for months for his meetings with Russian government officials - meetings that Sessions lied about at his confirmation hearing.
Comey himself had a riveting appearance before the same Senate panel last week, with some key moments centered on Sessions.
Sessions has been dogged by questions about possible additional encounters with the ambassador, Sergey Kislyak.
Sessions recused himself from the Russia investigation in March after it was revealed that he did not disclose two meetings he had with the Russian ambassador during the course of the Trump campaign.
Deputy Attorney General Rod Rosenstein will replace Sessions at the appropriations committees' hearing Tuesday. "My sense was the attorney general knew he shouldn't be leaving", Comey added.
Sessions will also likely be asked about his role in Comey's firing, about his recollection of a meeting in which President Donald Trump asked for him to leave the room and for his subordinate - Comey - to stay, and about reports that he recently offered Trump his resignation.