The Diamondbacks transferred Gallen (elbow) from the 15-day injured list to the 60-day IL on Monday.
The transaction opens up a spot on the 40-man roster for outfielder Lars Nootbaar, whom the Diamondbacks acquired from the Cardinals on Monday. The move also ensures that Gallen won't be available for the Diamondbacks until Sept. 7 while he recovers from right elbow inflammation. Following a recent meeting with arm specialist Dr. Neal ElAttrache, Gallen was cleared to start up a throwing program, and he's progressed to playing catch out to 120 feet as of Monday, per MLB.com. Gallen is set to undergo a follow-up MRI on Wednesday, and if the imaging reveals shows additional healing, the right-hander could be cleared to start throwing off a mound.