Prominent Department of Justice staffers are privately pooh-poohing aspects of T-Mobile’s $26.5 billion deal to buy rival Sprint — raising the potential it will face headwinds, The Post has learned.

The DOJ’s antitrust chief, Makan Delrahim, who could have final say over the deal, is among those who are “not impressed” with features of the planned marriage, including T-Mobile’s February promise to not raise cellular prices for three years, according to two people with direct knowledge of his thinking.

Senior Justice staffers say T-Mobile’s three-year cap on prices looks weak given AT&T’s seven-year timeout tied to part of its $85 billion takeover of Time Warner.

That tie-up, which was OK’d last month, limits AT&T from blacking out its Turner programming on rival cable companies’ platforms for seven years, which is how content companies sometimes renegotiate so-called retransmission fees.

Delrahim has yet to make his concerns known to Justice staffers, who are still reviewing the T-Mobile-Sprint merger in an effort to decide whether they think the agency should support it or sue to block it.

One reason for the silence may be that Delrahim has publicly spoken out against so-called behavioral remedies to win antitrust approval for deals because they tend to require companies to be monitored after a deal is cleared.

If approved, the proposed tie-up would marry the nation’s third- and fourth-largest wireless carriers. Opponents say it will put a damper on the cost-cutting war started by T-Mobile, which has surpassed Sprint as the nation’s third-largest carrier through its innovative pricing. Prices will then rise across the board, critics say.

T-Mobile has argued that buying Sprint will add as many as 5,600 new jobs and five call centers by 2021. The company, headed by colorful Chief Executive John Legere, also says the tie-up would help fast-track its development of a next- generation 5G wireless network.

Meanwhile, President Trump’s new attorney general, William Barr — Delrahim’s new boss — is planning to have a say in the deal despite owning stock in T-Mobile rival AT&T, sources said.

In his financial disclosure form signed Dec. 24, Barr disclosed that he contributes to Verizon Communications’ defined contribution plan and had AT&T vested stock options valued at between $250,000 and $500,000 and AT&T dividends valued at between $500,000 and $1 million.

“I think he ought to sell his stock in AT&T if he is going to have a role in this review,” Richard Painter, who served as chief ethics lawyer under President George W. Bush, told The Post.

“The whole point of an antitrust review is to understand what will be the impact on competitors,” like AT&T, Painter said.

The Justice Department declined comment.