That could happen Monday in Baltimore at the earliest, A's manager Bob Melvin said, keeping open the possibility of a riveting matchup at the Coliseum on Tuesday, with Gray potentially going against the Dodgers' Clayton Kershaw.
Gray was already disappointed to have missed the Blue Jays, who instead faced Jesse Chavez. The right-hander responded with six strong innings and, though hurt by Ryan Goins' three-run homer in the four-run outing, struck out nine and didn't walk a batter in the loss.
"The biggest thing for me, it was so sudden and so late that you really don't want to put your teammates in that situation," Gray said. "It happened the day before, so you put some guys in some tough spots, but Jesse responded well, and I was really happy to see that.
"You always want to throw against the best of the best and, right now, the way the Blue Jays are playing, it would have been fun, it would have been cool."
Gray said the back spasms were a first for him.
"That's why it was so weird," he said. "I was more freaked out than anything.
"It's not something super serious. It's more or less one of those things that is just uncomfortable, and there's really no reason at this point of the year to try to throw through something when you could just have a couple days and see how it responds."
After losing his passport in Toronto, Gray was simply happy to be standing at his locker in Baltimore on Friday afternoon.
"I didn't think I was going to make it out of the country," he joked.
Jane Lee is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.