The performer is still in critical condition, and has been in an undisclosed hospital since Thursday.
On his Web site his management team thanked everyone for their well wishes and prayers.
"Please remember Bret is, and always has been, a fighter and survivor and is under the best medical care possible," the post added.
Michaels had an emergency appendectomy April 12 after complaining of stomach pains before he was scheduled to perform at Sea World in San Antonio.
Michaels later wrote on his Web site that although the surgery "has taken its toll," doctors expected him to make a full recovery.
Michaels was the frontman for the '80s hair band Poison.
The Associated Press contributed to this report.