His return is still likely to come around the end of August at the earliest, assuming there aren't any complications.
Anderson, 25, has been limited to 38 starts over the last three seasons, because of four stints on the disabled list. He's posted a 1-4 record and 6.21 ERA in six games, five of them starts, this season.
Jeff Kirshman is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.