"We haven't made that decision yet," Gibson said. "This isn't the time to speculate, it depends on what happens this week."
Miley definitely won't pitch the next couple days and the team has an off-day on Thursday, so the next scheduled game for his spot in the rotation is on Sunday at Miami.
"There are so many things we're considering," Gibson said. "We reevaluate after every game, and there's a lot of things we're kicking around."
The D-backs could use the Thursday off-day to skip the fifth starter, but Gibson said he'd rather stay in turn.
"That's my plan today," he said. "I'm going to try to for sure. I want the guys to have an extra day of rest. It's really a good time for it."