Gallen (forearm) will be activated from the 10-day injured list to start Tuesday against Oakland, Jody Jackson of FOX Sports Arizona reports.
Gallen appeared to be potentially in line for a long absence after suffering a hairline fracture in his forearm in late March. As it turns out, he'll only wind up missing two turns in the rotation. He threw 67 pitched in a simulated game Wednesday, so he'll probably be asked to throw somewhere around 80 to 85 pitches in Tuesday's contest.