The State Department was unable to confirm whether the new March 31 meeting in Brussels will replace a planned foreign ministers' meeting that Tillerson will not attend on April 5 and 6.
Earlier this week, Tillerson caused dismay among Washington's European allies when his office announced that he would not be able to attend the meeting of the 28-member alliance.
But diplomats have been scrambling to find another date to accommodate the envoy from NATO's leading member.
"The Secretary of State will visit NATO in Brussels on Friday, March 31. The visit will come after his trip to Ankara, Turkey. Details about his schedule are forthcoming," a spokesman said.
Another official told AFP it was not yet clear whether the full foreign ministers' meeting would be brought forward to Tillerson's preferred date or if his talks would be separate.
Chinese leader Xi Jinping is expected to visit President Donald Trump in the United States in early April, and Tillerson would be expected to attend their meetings.
But his office has not confirmed that engagement, and word that Tillerson would stay away from the long-planned NATO talks raised questions about the United States' commitment to its allies.
NATO member Turkey's Foreign Minister Mevlut Cavasoglu has already announced that he expects to meet Tillerson in Ankara on Thursday, March 30.
On Tuesday, the State Department said that Tillerson would be represented in Brussels on April 5 and 6 by his acting deputy, career diplomat Tom Shannon.
After almost two months in the job, Tillerson has yet to appoint a deputy or any assistant secretaries, has largely avoided the media and works with a small inner circle of advisers.
The administration, meanwhile, has been scrambling to reaffirm its commitment to US military alliances after Trump called into question their usefulness during the presidential campaign.
Last week, after meeting Chancellor Angela Merkel, Trump claimed Germany owes "vast sums of money to NATO and the United States," reviving his charge that allies do not pay their way.
Defense Secretary James Mattis, a former Marine general, has declared US support for NATO, and last week Tillerson reaffirmed ties with Asian allies Japan and South Korea.
But Tillerson's absence from the alliance foreign ministers' meeting would have been noted with concern, especially by newer East European members on its exposed east flank.
The United States has worked with NATO to shore up support for the pro-western government in Kiev after Russia's annexation of Crimea and its support for a bloody uprising in eastern Ukraine.
Combined with economic sanctions, the deployment of more NATO troops from Western members to frontline Eastern allies in the Baltics and Poland was intended to send a signal to Moscow.
But during his presidential campaign, Trump raised eyebrows by expressing admiration for Russian President Vladimir Putin and dismissing NATO as "obsolete."
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