The record 22-time Olympic medallist has been listed among more than 500 athletes scheduled to compete at the Arena Grand Prix in Mesa, Arizona, between the April 24 and 26.
Phelps would be making his first competitive appearance in the pool since calling it a day after the 2012 Olympic Games in London if he does feature at the event, although the 28-year-old is yet to comment on his reported comeback.
It is not yet clear whether the most decorated Olympian of all time is eyeing a spot at the 2016 Games in Rio de Janeiro.
Phelps became a household name after winning six gold medals at Athens 2004, and surpassed that tally with eight in Beijing four years later.
The American added four more in London before calling time on his illustrious career, in which he won 18 Olympic golds.
Fellow Olympians Ryan Lochte and Katie Ledecky are set to compete at the same event later this month.