Phone: 925-454-6390. ValleyCare Physicians Associates at 5565 W. Las Positas Blvd, Suite 200. Phone: 925-416-5460. ValleyCare Physicians Associates at 5565 W. Las Positas Blvd, Suite 260. Phone: 925-416-5470. ValleyCare Physicians Associates at 5575 W. Las Positas Blvd, Suite 130. Phone: 925-463-0590..