"It showed much improvement," Black said.
Erlin had a previous MRI on May 21, and at that time there was some fluid in the elbow. He was placed on the 15-day disabled list, retroactive to May 18.
Black cautioned that Erlin is still a ways off from returning, but this latest round of good news was very welcome for an organization that has had plenty of bad news regarding pitchers in recent years.
"He's probably still three weeks away from rehab games," Black said.
Erlin is 3-4 this season with a 4.53 ERA in nine appearances, including eight starts.
Corey Brock is a reporter for MLB.com. Keep track of @FollowThePadres on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.