President-elect Joe Biden fractured his foot while playing with one of his dogs, his doctor said.
Mr Biden suffered the injury on Saturday and visited an orthopedist in Newark, Delaware, for an examination on Sunday afternoon, his office said.
A subsequent CT scan "confirmed hairline (small) fractures of President-elect Biden's lateral and intermediate cuneiform bones, which are in the mid-foot", according to a statement from his doctor, Kevin O'Connor.
"It is anticipated that he will likely require a walking boot for several weeks," he added.
Leaving the doctor's office to head to an imaging centre for his CT scan, Mr Biden was visibly limping, though he walked without a crutch or other aid.
He was under examination for more than two hours after arriving at the office on Sunday afternoon.
Mr Biden sustained the injury playing with Major, one of the Bidens' two dogs.
They adopted Major in 2018, and acquired their first dog, Champ, after the 2008 election.
The Bidens have said they will be bringing their dogs to the White House and also plan to get a cat.
At 78, Biden will be the oldest president when he is inaugurated in January, but he frequently dismissed questions about his age on the campaign trail.
He released a doctor's report in December that disclosed he takes a statin to keep his cholesterol at healthy levels, but his doctor described him as "healthy, vigorous" and "fit to successfully execute the duties of the Presidency".