Ross, who will turn 25 in a week, last pitched on Thursday for Triple-A Sacramento. In two starts with the River Cats, he was 0-1 with a 4.00 ERA. He surrendered four runs with three walks and four strikeouts in nine innings.
The A's are not expected to officially promote Ross until Tuesday, at which point they will have to make a corresponding move on their 25-man roster. The decision won't be an easy one.
Oakland has two left-handed-hitting first basemen in tow, so it might make sense for the A's to cut ties with Kila Ka'aihue -- at least it did before Sunday. Ka'aihue collected three hits and raised his average to .500 (6-for-12) in four games.
It's also possible that the A's might option Collin Cowgill, since they have five other outfielders on their roster. But manager Bob Melvin likes having a true fourth outfielder, since Jonny Gomes and Seth Smith have solely been used as designated hitters up to this point.