Two top advisers to Beto O'Rourke's presidential campaign have left the former Texas representative's team.

Becky Bond and her deputy Zack Malitz, who were involved in the Democrat's failed 2018 Senate election against Republican incumbent Sen. Ted Cruz, are no longer employed by the campaign, O'Rourke spokesman Chris Evans told Buzzfeed News. Evans, however, did not respond to questions about why the pair left and whether their departures were voluntarily.

[Related: Top Beto O'Rourke adviser is socialist who slammed Saul Alinsky as a moderate]

Bond and Malitz's exits come after O'Rourke named Jen O’Malley Dillon, a highly respected alumna of both of former President Barack Obama's White House bids, as his campaign manager. The hire was interpreted by many observers as a move to professionalize O'Rourke's efforts to become his party's standard-bearer after he shunned political consultants and pollsters ahead of his 2018 contest.

Bond and Malitz were only temporary aides brought on to help get O'Rourke's 2020 structure "off the ground" and "remain close friends of the campaign," Evans told BuzzFeed News, despite Bond reportedly telling fellow Democratic operatives she was more integral to the operation.

“Launching a presidential campaign without a big staff or even a campaign manager was no easy feat and it took everyone pitching in,” Bond said in a statement. “We’re proud to have been part of the team of deeply dedicated staff and volunteers who nearly pulled off a historic upset in the 2018 Texas Senate race and broke records launching Beto’s campaign for the presidency.”

Bond, a liberal activist who co-founded the CREDO SuperPAC, and Malitz previously worked for Sen. Bernie Sanders' 2016 presidential campaign. They are credited as being the architects behind the senator's energized network of grassroots support.

Before O'Rourke announced in March that he was vying for the Democratic nomination, he was repeatedly criticized by Sanders' allies for his moderate campaign positions and voting record as a member of Congress. As a presidential candidate, he has questioned whether the self-described socialist's signature "Medicare For All" proposal is the best to rollout universal healthcare across the country.