Phelps' coach, Bob Bowman, announced Monday on the final day of the U.S. trials that Phelps was scratching the 200-meter freestyle.
"It's so much smarter for me to do that," Phelps said. "We're not trying to re-create what happened in Beijing. It just makes more sense."
Phelps qualified in five individual events for London and is expected to swim all three relays. But, on Bowman's recommendation, he will focus on the 200 and 400 individual medley and the 100 and 200 butterfly.
"This is an event program that I'm very confident that I can do and do better than I did here," he said, referring to his results in Omaha.
Bowman said his main concern was Phelps' being fresh for the 400 freestyle relay. While the U.S. has traditionally dominated that event, Australia is favored in London. The relay was one of Phelps' closest calls in Beijing, with teammate Jason Lezak coming from behind on the anchor leg to beat a strong French squad.
The relay final is on the same day as the preliminaries and semifinals of the 200 freestyle.
"The 400 free relay is going to be harder than it was last time," Phelps said. "It just allows me to put my energy elsewhere instead of trying to control it for another three races."
Phelps has to swim preliminaries, semifinals, and finals in the 200 IM, and the 100 and 200 butterfly. The grueling 400 IM, which opens the swimming competition July 28, has prelims and finals.
Now 27, Phelps hasn't adhered to the rigid training schedule he was on for years leading up to Beijing. After the 2008 Games, he took time off and showed little interest in resuming the grind that had prepared him to win eight events.
With Phelps dropping the 200 free, Ricky Berens moved up to claim his first individual spot on the Olympic team. He was already scheduled to swim the 400 and 800 free relays.
Dropping the 200 free also removes one of Phelps' showdowns with American rival Ryan Lochte, the defending world champion. They will now face each other in just the two individual medleys.