The US official declined to confirm media reports that the United States has nominated Robert Ford, a career diplomat with experience in Arab countries like Algeria and Iraq, his most recent posting.
He would be the first US ambassador to Damascus since the one recalled after former Lebanese prime minister Rafiq Hariri was killed in a bombing blamed on Syria on February 14, 2005.
President Barack Obama's administration announced February 3 that it had nominated an ambassador to Syria as part of its year-long drive to engage a former foe in efforts to promote Arab-Israeli peace.
In line with diplomatic protocol, Syrian Foreign Minister Walid Muallem noted from Damascus at the time that Syria had "the right to study" the proposed appointment.
There was no immediate confirmation from Damascus that it had accepted the US nominee.
The news comes as the administration announced that senior diplomat William Burns will travel to Syria next Tuesday for talks with President Bashar al-Assad on "furthering dialogue... on all aspects" of US-Syrian ties.
But the senior US official told AFP there was not "necessarily" a link between Burns's trip and any White House announcement.
State Department spokesman Philip Crowley said earlier that the visit by Burns, the assistant secretary for political affairs and the State Department's number three diplomat, "doesn't have to do with the ambassador per se."
However, Crowley added: "It has to do with what a return of the ambassador to Syria represents, which is, you know, further steps in terms of our bilateral relations."
Burns, a former US ambassador to Jordan who speaks Arabic, will "reflect on a number of issues in terms of regional issues... how Syria continues to view... the situation with respect to the Middle East peace," Crowley said.
Burns, who will also meet Syrian Foreign Minister Walid Muallem, will travel to Syria from Beirut where he will hold talks Monday with Lebanese President Michel Sleiman, Prime Minister Saad Hariri, and others, Crowley said.
The White House said Obama told Saad Hariri in a telephone call Friday that he strongly supports bringing to justice the killers of his father.
An international tribunal based in The Hague was set up by a UN Security Council resolution in 2007 to try suspects in the murder.
US support for the tribunal has strained ties with Syria.
A UN commission of inquiry initially said it had found evidence to implicate Syrian and Lebanese intelligence services but there are no suspects in custody.
The State Department said that Burns will travel to Turkey on Wednesday before wrapping up his regional trip in Azerbaijan on Thursday.
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