WASHINGTON — Former Georgia Sen. Sam Nunn appears to have dropped from the running to be Barack Obama’s vice presidential choice.

The Georgia Democrat will be traveling out of the country until Monday, his spokeswoman said Thursday. Obama is scheduled to appear with his running mate on Saturday in Springfield, Ill.

Cathy Gwin, Nunn’s spokeswoman at the Nuclear Threat Initiative, declined to offer details of Nunn’s trip but said he was traveling on international business.

A moderate Southerner with strong foreign policy credentials, Nunn has been widely discussed recently as a possible running mate for Obama. At a forum at Saddleback Church earlier this month, Obama cited Nunn as one of three people — along with Obama’s wife and grandmother — on whom he would rely for counsel as president.

Nunn has advised Obama’s campaign on the ongoing conflict in the Caucasus between Russia and Georgia, and the two Democrats also appeared together at a Purdue University panel discussion last month on global threats.

All along, Nunn has downplayed the likelihood that he would be chosen.

“If anyone offered me any high office in U.S. government, I’d be greatly honored and I’d talk to him. Certainly I would talk to Sen. Obama if he wanted to talk about it, but I think the chance of an offer are pretty slim,” Nunn said at the Purdue forum in July.

Nunn, who turns 70 in September, was chairman of the Senate Armed Services Committee and was widely viewed as the chamber’s foremost authority on foreign and military affairs when he retired in 1996 after a 24-year career. He remains active in international affairs, particularly as CEO of the Nuclear Threat Initiative, a Washington-based group that Nunn formed with CNN founder Ted Turner to fight the global spread of nuclear materials.