CQ Politics in Washington, D.C., reports that Ross recently attended a National Republican Congressional Committee "candidate school."
Nunnelee of Tupelo attended the training several months ago. He has raised $220,000 and aims to unseat Democratic Rep. Travis Childers of Booneville in the 2010 election.
Ross, who's been talking about a run since early 2009, said he intends to make a decision "after the first of the year," CQ reports.
"We're still traveling the district and meeting people and talking to people about the race," he said.
Ross, a lawyer and Navy veteran, was mayor of Eupora from 1997 to 2001. In the George W. Bush administration, he was senior counsel at the Justice Department.