Updated

Michael Phelps could have a showdown with rival Ryan Lochte on the very first day of the U.S. Olympic swimming trials.

USA Swimming announced Sunday that Phelps passed on the deadline to scratch from the 400-meter individual medley, meaning the winningest Olympian ever will at least swim the preliminary round Monday morning. Should he qualify for the evening final and decide to race it, he likely would be pitted against Lochte and Tyler Clary, who went 1-2 in the event at last year's world championships.

Phelps will swim in the 10th of 12 prelim heats. Clary will go in the 11th, followed by Lochte in the final heat.

"We would like to see what he can do in the event," Phelps' coach, Bob Bowman, said in a text message to The Associated Press. "He's done a few decent ones in season, so we are taking a shot and seeing how it goes."

Phelps won the 400 IM at the last two Olympics, but vowed after Beijing to give up the grueling event that requires all four strokes. He had a change of heart, putting the race back in his program at several Grand Prix meets leading up to Omaha.

Lochte said Saturday he looked forward to facing Phelps in as many events as possible.

"He's the world's best swimmer ever," Lochte said. "I love racing against him. It's fun. He's one of the hardest racers in the world. He'll go toe-to-toe with you until the end. That's excitement for me. I really hope he does swim that."

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