Estrada (knee) threw a bullpen session Saturday, his first since landing on the injured list June 5, Jeff Sanders of The San Diego Union-Tribune reports.
Estrada is in the midst of his second IL stint of the season, as he previously missed just under a month earlier in the campaign due to elbow tendinitis. The right-hander has had a slower recovery than expected from right knee inflammation, but his ability to get back on the mound represents a major step forward in the recovery process. He's expected to throw a couple more bullpen sessions this week before he resumes facing hitters after the All-Star break.