"First day back on the course in 17 days ... there has been a lot of rest and rehab ... it felt good to be back out with the boys!" he wrote accompanying a video that showed him making a smooth swing with an iron.
World number eight Fowler pulled out of last week's Northern Trust tournament and this week's Dell Technologies Championship to give the injury a chance to heal.
Fowler revealed he was suffering from the injury before the PGA Championship, where he finished tied for 12th.
An MRI later diagnosed a partial tear to the oblique muscle on the right side of his abdomen.
Fowler's next chance to play will be at the BMW Championship outside Philadelphia next week.
The Ryder Cup will be played from Sept. 28-30.
(Reporting by Andrew Both in Cary, North Carolina; Editing by Greg Stutchbury)
