Montas was reinstated from the paternity list Friday, according to an A's press release.
The A's already have their starters set for Friday and Saturday with Chris Bassitt and Jesus Luzardo, but this frees up Montas to start Sunday agains the Giants if Oakland decides that's the way it wants to go. Montas has an ugly 5.86 ERA in nine starts this season and has only one victory in his last five outings. He has not made it through six innings in any of those five games.