Injuries to three Sea World trainers in the last three months prompted a decision Monday by park officials to temporarily exclude stunts in which trainers join the killer whales in the pool.
Jackie Hill, a spokeswoman for the aquatic park, said she did not know when trainers would again join the whales in the water.
"I don't know how long it will be," Hill said. "We have to act according to our comfort level. Of course, we are concerned about John."
John Sillick suffered internal injuries and broken ribs, a broken pelvis and a broken leg when a 12,000-pound killer whale landed on him during a show Saturday. Sillick, 26, a trainer at the park for two years, remains in serious condition at UC San Diego Medical Center, where he underwent abdominal surgery Saturday and had surgery for the broken bones Sunday, a hospital spokeswoman said.
He was injured when a whale leaped out of the water and came down on the whale Sillick was riding, Hill said.
Sillick had signaled to the whale to do a natural "breach" behavior in which the whale propels itself out of the water, turns sideways and falls back into the water.
Trainer Chris Barlow was slightly injured Sept. 30 after a whale bumped into him during a performance. Two days before, trainer Mark McHugh was bitten on the hand by a whale during a training exercise.
Barlow and McHugh have since returned to their jobs at Sea World.