ASSOCIATED PRESS/Eric Gay, File Rep. Beto O'Rourke (D-Texas), the 2018 Democratic nominee for U.S. Senate in Texas, makes his concession speech at his election night party in El Paso, Texas.

The progressive commentariat has been buzzing in recent weeks about the barrage of unflattering reporting and criticism directed at retiring Texas Rep. Beto O’Rourke (D) by left-leaning journalists and activists.

Although Vermont Sen. Bernie Sanders’ team insists he has had nothing to do with the criticism and there is no evidence to suggest he has, many of his supporters have indeed been peeved by the boomlet of hype around O’Rourke following his 3-percentage-point loss in the race for a Senate seat in Texas.

But there is a specific factor driving the frustration of some diehard “Berniecrats” that has thus far received little attention: The defection of key alumni from Sanders’ 2016 presidential run to the O’Rourke camp and the resulting worry that they will provide a progressive coat of paint for the Texan’s more moderate record.

Becky Bond and Zack Malitz are two of those figures. The pair had a major role in shaping Sanders’ innovative “distributed” organizing model that the candidate used to empower decentralized, self-organizing groups of volunteers in lieu of a much larger, more expensive cohort of field staff. They masterminded a similar setup for O’Rourke in his 2018 Senate run.

Bond and Malitz have already pledged themselves to O’Rourke if he jumps into the presidential race.

“They are using their Bernie credibility to whitewash Beto’s policies,” said a progressive strategist sympathetic to Sanders who declined to be named for professional reasons. “It’s Bernie-washing.”

As for those policies, progressive critics point to a number of examples. O’Rourke, a member of the business-friendly New Democrat Coalition, has voted for bills lifting the ban on exporting crude oil and granting presidents a fast-track approval process for international trade agreements. Over three terms in Congress he also failed to sign on to a single-payer health care bill that had the support of the majority of House Democrats, though as a Senate candidate he said that if elected, he would support Sanders’ Medicare for All bill.

Bond and Malitz aren’t the only Sanders alumni likely to bolt for O’Rourke’s team if he runs.

O’Rourke also tapped Middle Seat, a digital strategy and fundraising firm founded by Sanders alumni Kenneth Pennington, Hector Sigala and Elizabeth Bennett, to run the digital operation for his Senate campaign. And Linh Nguyen, another former Sanders digital staffer, migrated to O’Rourke’s Senate campaign as well.

The New York Times reported that Middle Seat is “hoping” to join a potential O’Rourke 2020 bid as well; Pennington declined to comment in response to a HuffPost inquiry.

Sanders’ most ardent supporters say they are not worried that O’Rourke will deprive Sanders of top organizing firepower or signal an exodus of former Sanders talent to the O’Rourke team in the event that both men run for president.

Tim Tagaris and Robin Curran, who led Sanders’ digital fundraising team, have already pledged to return to the Sanders fold, according to the Sanders campaign. And Pennington had a public falling out with Jeff Weaver, Sanders’ longtime adviser and 2016 campaign manager, in August 2016, long before O’Rourke became a nationally recognized figure.

Sanders’ midterm campaign swing showed there “is a tremendous outpouring of support [for him] that still exists at the grassroots level,” Weaver told HuffPost. “I have an email inbox and voicemail full of messages from former staffers who want to rejoin a campaign if it happens.”

Weaver would not comment on O’Rourke or any other potential candidates.

But some Sanders loyalists nonetheless fear that the presence of some high-profile Sanders alumni closely associated with Sanders’ most successful tactics will obscure O’Rourke’s centrist policy record.

“People are saying O’Rourke is a bridge to the Bernie wing because of Zack and Becky,” the progressive strategist said.

Even if Bond, Malitz and other Sanders alumni have not magnified O’Rourke’s notoriety by association, they certainly have done so by leveraging the Sanders playbook to help O’Rourke succeed, according to Charles Lenchner, a co-founder of The People for Bernie Sanders, a pro-Sanders group with a big social media following that is not tied to the campaign.