US artistic swimmer Anita Alvarez, who was dramatically rescued from the bottom of the pool after fainting in her solo routine, was omitted from the team event on Friday at the request of governing body FINA.
"That was a decision FINA had made," said Selina Shah, US artistic swimming's team doctor.
"In my opinion she could have competed, I am very confident," Shah said.
FINA said it had organised a medical examination on Friday morning that included three representatives of its medical committee, its executive director, Dr. Shah and US team officials.
"Following these discussions, FINA determined that Anita Alvarez should not compete today," FINA said in a statement.
"The health and safety of athletes must always come first. While FINA understands why this decision will have been disappointing to the athlete, it was a decision that was made with her best interests in mind.
The governing body said it was "delighted" that Alvarez had made "such a strong recovery" and looked forward to seeing her in competition again soon.
Shah said she did not know how FINA had reached its conclusion that Alvarez should not compete.
"I'm not aware of their decision making process."
Alvarez fainted and dropped to the bottom at the end of her individual routine on Wednesday and was saved by her quick-thinking coach, Andrea Fuentes.
