The message left by Frank DeLeo was retrieved by police from the cellphone of Dr. Conrad Murray and played during the trial of a negligence lawsuit filed by Jackson's mother against concert promoter AEG Live.
"I'm sure you're aware he had an episode last night," the message said. "He's sick ... We gotta see what he's doing."
Plaintiff's lawyer Brian Panish acknowledged outside court that the episode occurred on the day Jackson was told by Kenny Ortega, the director of his "This is It" concert, to go home from a rehearsal because he was pale and shivering.
Panish suggested that if DeLeo was aware of the incident, so were AEG executives.
The lawsuit claims AEG didn't properly investigate Murray, who was later convicted of involuntary manslaughter after prosecutors said he gave Jackson a lethal dose of the anesthetic propofol.
Jurors were not given any further details on the episode.
Katherine Jackson and her daughter Rebbie sat in a front row of the courtroom during testimony.
AEG denies it hired Murray, and it is likely to blame Jackson for insisting on having Murray as his doctor because of his dependence on propofol, which Jackson used to sleep.