Williamson (shoulder) tossed a bullpen session Saturday, his first since landing on the injured list April 30, Charlie Goldsmith of Fox 19 Now Cincinnati reports.
Though Williamson is expected to remain out through the All-Star break, he's making progress with his throwing program at the Reds' facility in Arizona and could be ready to start facing hitters within the next two or three weeks. Williamson posted a 6.11 ERA and 1.64 WHIP in 28 innings over six starts with Cincinnati before being deactivated due to left shoulder fatigue.