The White House on Monday acknowledged that Vice President Joe Biden is still weighing a possible run for the top job, amid controversy surrounding Democratic frontrunner Hillary Clinton.
Biden, President Obama`s deputy for nearly seven years, has previously said he would make a decision on entering the 2016 race by the end of the summer.
"I would assume that that means he`s got a another month or so to think about this and announce a decision," said White House spokesman Josh Earnest.
Obama has so far been careful not to pick among the Democratic candidates.
But several close aides have jumped from the White House to Clinton`s campaign in recent months.
Her struggles to explain why she used a private email server to conduct state business has raised questions about her status as presumptive nominee.
Democrats have long been concerned about the prospect of a half-hearted primary race leading to Clinton`s nomination.
Biden would provide Clinton with stiff competition, but his path back to the White House is not entirely clear.
He has been a presidential candidate twice and twice lost badly.
Earnest did not rule out the possibility that Obama would ultimately chose between his vice president and his former secretary of state.
"I wouldn`t rule out an endorsement," he said.
Speculation about Biden`s plans were fueled by reports over the weekend that he had met privately with Senator Elizabeth Warren, an influential voice in the Democratic Party`s left wing.