Ochoa won two majors and reached No. 1 in the world with David Brooker, but she said Tuesday they are parting because of a new phase in her career.
Its not easy to let him go knowing he is such a great caddie and person, Ochoa said.
Johnston spent a dozen years working for Juli Inkster, and together they won 20 times and four majors. He left Inkster to work for Michelle Wie when she was 15 and had at least a share of the lead on the back nine of three majors. He also has worked for Brittany Lincicome, Suzann Pettersen and Angela Park.