The 54-year-old said before Sunday's matinee against the Dodgers that the sickness was "something" with his stomach.
He left Saturday night's game early and bench coach Alan Trammell took the reins from there.
"I planned on it yesterday," he said about managing. "It kind of came on when I got here yesterday."
He said he watched some of the D-backs' 5-3 loss to the Dodgers from the clubhouse and the rest from his home.
"It doesn't matter," he said. "Let's move on."
Gibson has a career managerial record of 95-101 entering Sunday.