"Animals who have been involved in incidents like this in the past have been allowed to continue performing," SeaWorld San Diego spokesman Dave Koontz said.
Park trainers were examining the whale, a female orca named Kasatka, and trying to determine what made her grab her trainer, Ken Peters, Koontz said.
Peters, 39, remained hospitalized with a broken foot after the whale grabbed him and twice held him under water during a show. He had a fractured metatarsal in his left foot but was in good spirits, Koontz said.
Peters was hurt around 5 p.m. Wednesday during the final show of the day at Shamu Stadium, a 36-foot-deep tank.
The show's finale called for Kasatka to shoot out of the water so Peters could dive off her nose. The whale is about 17 feet long and weighs well over 5,000 pounds.
As several hundred spectators watched, the whale and trainer plunged under water, where Kasatka grabbed Peters by the foot and held him for less than a minute before surfacing, Koontz said.
"The trainer was being pinned by the whale at the bottom of the pool," Karen Ingrande told KGTV-TV.
When they came up, Peters tried to calm the animal by rubbing and stroking its back but it grabbed him and plunged down again for about another minute.
The crowd "began to realize there was not something right and the whale was down again under the water. Again they were splashing the water to try to get the whale to come to the surface," Ingrande said.
The whale finally released him and Peters was able to surface and swim away. Other trainers stretched a net between him and Kasatka, Koontz said.
He emerged from the tank with one leg of his wet suit torn.
"He tried to stand up on the stage and that's when we realized there was something wrong with his leg and his foot. He was just white as a ghost," spectator Sherri Justice told KFMB-TV in San Diego.
Mike Scarpuzzi, who oversees zoological operations, said Peters has been working with animals for 16 years, including 12 spent at Shamu Stadium.
"His skills and techniques, and close relationship with the whale played a major role in helping the animal calm down and allowed him to eventually swim out of the pool," Scarpuzzi said.
The park planned to continue the Shamu Stadium shows Thursday using other whales. The park has a total of seven killer whales, including two of Kasatka's offspring, Koontz said.
He did not know whether Kasatka would be allowed to perform.
Koontz said trainers from the San Diego park and sister parks in San Antonio and Orlando, Fla., planned to confer Thursday and review the incident in an effort to figure out what made the orca grab Peters.
Koontz said the 30-year-old orca had been performing most of her life and was familiar with the routine.
"She's been one of our strongest, most consistent performers," he said.
Koontz said a different whale dived with a trainer's foot in its mouth two or three weeks ago but obeyed commands to release the trainer and return to the side of the tank. The trainer was not injured.
SeaWorld officials reported in 1999 that Kasatka tried to bite a trainer during a show, but he was unhurt.