"Just a little bit," Black said. "I think it was three sets of 10 swings. Obviously, it is not 100 percent intensity or effort."
This is the first time Myers has done anything significant with a bat since May 12.
"It's the first step in the progression he'll take," Black added.
Myers, who was injured May 9, against the D-backs, is still wearing a brace on the wrist most of the day. He attempted to hit during batting practice three days later in Seattle, though he had pain.
Myers was eligible to be reinstated from the disabled list on May 26, but will need more time to let the wrist fully heal. Myers had images taken last week that showed the tendinitis was dissipating, though he still encountered some pain.
Myers was first diagnosed with tendinitis near the extensor carpi ulnaris, a muscle located on the little finger's side of the forearm that is used to extend the wrist.
The Padres are 7-10 without Myers, who started the season in center field but then shifted over to first base after Yonder Alonso landed on the disabled list May 8 with a right-shoulder bruise.
Black said there's still no timetable as to when Myers will progress to taking batting practice or when he'll increase the volume and intensity of his swings.
"He came out of that little exercise fine," Black said of Saturday's session. "… We'll continue to slowly progress his swings with effort and volume as we move forward.
"It's a good sign that he swung and there wasn't any pain. But, again, it wasn't at 100 percent [intensity]."
At the time of the injury, Myers was leading the team in hits and runs and was hitting .291 with five home runs and 19 RBIs.
Corey Brock is a reporter for MLB.com. Keep track of @FollowThePadres on Twitter and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.