The team did not have many second base options in 2013, and there were a couple of times where Mark Reynolds had to play second. Kelly will be that backup. He posted just a 99 OPS+ in 2013, but owns a career .253/.335/.427 slash. He does have some power, and his left handed swing should play well in Yankee Stadium.He has experience at at second, third, and the outfield, and he’s a much better offensive player than Jayson Nix or Eduardo Nunez.
Outside of a backup option to Cano, Johnson played third base with the Rays in 2013 and looked good in limited time. His UZR/150, DRS, and RZR all say that he has a plus glove at the hot corner (small sample size), and there’s a chance he’s one of the plans to replace Alex Rodriguez. For what it’s worth, Johnson hits lefties just as well as he does righties, and Mark Reynolds might not be an upgrade if they want a platoon at third base.