This machine is still model A1286 so I see no reason for the standard 9.5 optical bay adapter not to work: 9.5 mm SATA Optical Bay SATA Hard Drive Enclosure
Add a hard drive to your laptop by replacing the optical drive with a second hard drive. Compatible with all Unibody MacBooks and Unibody MacBook Pros (excluding MacBook Pro Retina). 9.5 mm Internal SATA Optical Bay for SATA Hard Drives. — 21 available at 39.95 each.