However, Contreras, who has passed his final rehab test, now is virtually certain to be activated when the Pirates come off the road to open a five-game homestand on Friday against the Nationals.
There wasn't anyone meriting giving up their seat in the Bucs' elite bullpen -- until Sanchez's demotion there after his abridged Friday night start.
Sanchez's next turn in the rotation will come on Wednesday in Milwaukee. Although manager Clint Hurdle would not comment Sunday morning -- "We'll make a decision [Monday] on a Wednesday starter," he said -- the most likely scenario has Jeanmar Gomez making that start and Sanchez remaining a long man in the bullpen.
When Contreras joins up with the Bucs, he figures to push Sanchez out. Simple, theoretically.
Contreras' final back-to-back outings for Triple-A Indianapolis were pushed up to Friday and Saturday. He allowed one hit, a solo homer, in the two games, striking out three without a walk.
"He was in good form," Hurdle said. "He will have two days down, and we'll see how he feels. Then he'll either get another opportunity to pitch [with Indianapolis] or be activated here."
As for the discipline and his appeal of it, Sanchez said, "I respect the rules. But I was just pitching and a pitch got away from me. They've got to hear my version of what happened."
Tom Singer is a reporter for MLB.com and writes an MLBlog Change for a Nickel. He can also be found on Twitter @Tom_Singer. This story was not subject to the approval of Major League Baseball or its clubs.