Cahill began the season on the disabled list next to five other A's players, including fellow pitchers Michael Wuertz and Joey Devine. He said the neck pain began at the end of last season and resurfaced after his Minor League start on March 29.
The 22-year-old pitcher made 32 starts as a rookie last season and was expected to have the edge for the fifth rotation spot entering camp. However, his injury -- combined with a strong showing from Gio Gonzalez -- led the A's to go with the left-hander.
Manager Bob Geren noted that Cahill is seemingly only a week behind other pitchers. But where the righty fits into the A's picture after fully recovering is unknown. There is no timetable for his return.