Secretary of Defense Mark Esper has recused himself from any decision on the Pentagon’s controversial contract for the Joint Enterprise Defense Infrastructure cloud, after having spent months reviewing the procurement.

In a statement, Chief Pentagon Spokesperson Jonathan Rath Hoffman said Esper is recusing himself from the decision because his adult son works for one of the original bidders.

“Although not legally required to, he has removed himself from participating in any decision-making following the information meetings, due to his adult son’s employment with one of the original contract applicants,” Hoffman said. “Out of an abundance of caution to avoid any concerns regarding his impartiality, Secretary Esper has delegated decision making concerning the JEDI Cloud program to Deputy Secretary [David] Norquist. The JEDI procurement will continue to move to selection through the normal acquisition process run by career acquisition professionals.”

The original bidders were Oracle, IBM, Amazon Web Services and Microsoft. Only Amazon and Microsoft remain in consideration. IBM confirmed that the secretary’s son, Luke Esper, is a consultant for the company.

“Sec. Esper’s son has been a digital strategy consultant with IBM Services since February. His role is unrelated to IBM’s pursuit of JEDI,” an IBM spokesperson said.

The contract is potentially worth $10 billion over 10 years.

Esper, who announced he was reviewing the contract in August shortly after his confirmation, said previously that he was spending two hours a week learning about the procurement. Pentagon CIO Dana Deasy back in August called the briefings on the contract “deep education sessions” to teach him about the contract.

This is yet another setback for the JEDI contract. After a contentious pre-award fight led by Oracle, the delayed contract is still under review by the Pentagon Inspector General, stuck in the U.S. Court of Appeals for the Federal Circuit and has drawn continuous scrutiny from Congress. Much of the fight over the contract has centered around conflict-of-interest allegations against several DoD employees who had previously worked for the Amazon.

The DoD did not immediately respond to comment about which contractor Esper’s son worked for, why it took several months for the recusal after the review began, and if Norquist would undergo similar education sessions that Esper attended.