Anderson (knee) played catch Tuesday and is scheduled to throw a bullpen session Wednesday, Ben Weinrib of MLB.com reports.
Anderson continues to rehab his way back from the arthroscopic knee surgery he underwent in early July to dissolve the left knee inflammation that was afflicting him. The lefty remains without a timetable for return, though he's certainly making solid progress. He'll likely require a minor-league rehab start or two before rejoining the big-league club.