Not just yet.
"Figure, why not give it a shot?" he said at a news conference in Irvine, Calif. "Like I said before, I'm probably not in the best shape I want to be to swim that race. We'll see if we can make worlds. And if we can make worlds, I'll know what to do to put my body in shape for next summer to be able to swim the kind of times and level I want to swim."
The major international meet starts Wednesday in Irvine, and Phelps is swimming four individual events: the 200 butterfly, 400 IM, 100 butterfly and 200 IM. Thursday will be the 400 IM, a showdown against American teammate and rival Ryan Lochte.
Lochte defeated Phelps in the 200 IM at the recent national meet, also in Irvine, and has been teasing him good-naturedly about leaving the 400 IM off the program.
Bob Bowman, Phelps' coach, saw an indication that this might happen when he showed interest in the way the event would unfold at the nationals. After all, Phelps is the world-record holder in the 400 IM.
"The morning before the final, he completely forecast how the race would be swum," Bowman said. "He was uncannily close: 'Ryan's going to go [4 minutes, 9 seconds]. Tyler [Clary] is gonna take it out too fast.' He had a whole scenario done.
"I was like, 'Are we really going to send 4:14 to the world championships?' He was like, 'I don't know about that.' He thought maybe he could try it."
Phelps joked that his mother, Debbie, would be most pleased about the resumption of the 400 IM.
"She said that's her one favorite where she can just relax a little bit," he said. "She's not going to be here, so she won't be able to watch it. She told me to call her afterward."