Previously Trumbo had taken swings while kneeling on one knee.
"As good as I could have hoped for," Trumbo said. "Everything felt good."
Trumbo has also begun to run on the AlterG treadmill, which offloads a percentage of a person's body weight. As of now, Trumbo is running on just 20 percent of his body weight.
Steve Gilbert is a reporter for MLB.com. Follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.