Gallen (elbow) will throw a simulated game Friday, Nick Piecoro of The Arizona Republic reports.
Both Gallen and Michael Soroka (shoulder) will toss sim games Friday with the hope of returning to the team next week. Gallen has been sidelined since July 7 with right elbow inflammation. He made a rehab start with Triple-A Reno over the weekend, allowing a hit and walking two with two strikeouts across 1.2 frames. Gallen is aiming for 60 pitches Friday.