They're the first swings Jackson has taken since he tried to take batting practice last week in Cleveland and was shut down after a round. Jackson also did some running, though that was the extent of his baseball activities.
Jackson will be re-evaluated on Friday to get a better idea how close he is to a return. At this point, though, the Tigers don't have an estimate on it.
Jackson went on the disabled list retroactive to May 17 with an abdominal strain. Quintin Berry has played well in Jackson's absence, but he entered Thursday batting 2-for-13 in Detroit's four-game series vs. Boston with nine strikeouts.