Glasnow (forearm) engaged in a fastball-only throwing session Saturday, Juan Toribio of MLB.com reports.
It was the first time throwing off a mound for Glasnow since he suffered his forearm strain. The right-hander didn't overextend himself, as the catcher stood only a few feet in front of him. Glasnow will next throw a bullpen session Tuesday or Wednesday, which would represent another notable step in his recovery.