Gallen retired all six batters faced, striking out one, in two scoreless innings of a spring game against the Giants on Monday.
Aside from an extended at-bat after starting 0-2 against San Francisco first baseman Brandon Belt, Gallen impressed in his Cactus League debut. It would be shocking if the right-hander opens anywhere other than Arizona's rotation. and he'll perhaps be slotted as high as third, but the Diamondbacks have not yet confirmed Gallen's role.