President Trump's team reportedly fears what former White House counsel Don McGahn told special counsel Robert Mueller as part of his Russia investigation.

The Justice Department is expected to release a redacted version of Mueller’s report on Thursday, which follows the four-page summary of the report Attorney General William Barr submitted to Congress last month.

The White House has already been briefed on the report, stoking some concerns among Trump’s team.

Although Barr's summary said Mueller did not find collusion between the Trump campaign and the Kremlin during the 2016 election, ABC News’ Chief White House Correspondent Jon Karl said, "There is significant concern on the president's team about what will be in this report."

During an appearance on "This Week" on Sunday, Karl said, "What worries them most is what Don McGahn told the special counsel."

The White House did not immediately respond to a request for comment from the Washington Examiner.

McGahn suggested during a recent off-the-record lunch that aides may learn more about his interactions with Trump during his time at the White House, according to Axios.

"I spent the last couple of years getting yelled at," McGahn said, according to two sources that attended a lunch earlier this month with McGahn and Republican Senate aides. "And you may soon read about some of the more spirited debates I had with the president."

McGahn left the Trump administration last fall, after which he rejoined his former law firm, Jones Day. McGahn sat with Mueller's team for at least 30 hours over multiple interviews, without his lawyer offering a full debrief to the president's attorneys on what was said during those meetings.

Justice Department spokesperson Kerri Kupec said Monday a redacted version of Mueller’s nearly 400-page report will be released on Thursday. The redactions will cover details on grand jury material, foreign intelligence that could compromise sources and methods, and derogatory information about people who were not charged.

According to Barr's summary, Mueller also did not make a final determination on whether Trump obstructed justice. Barr wrote he and Deputy Attorney General Rod Rosenstein determined there was insufficient proof to establish such a crime.