Throughout the history of the greatest Yankee teams, they have always had a balance between lefty and righty hitters, and if you can get that mix with players from both sides of the plate that compliment one another, that is the way to go. Before the DH in the DiMaggio era, the Yanks had five lefty bats, and mostly during the Mantle era, they carried four from the left side; when Jeter came along, those who took the field were split in half as to which side that they batted from. Of these teams, the one constant was that they always had a left handed hitting catcher in Dickey, Berra and Posada who was a switch hitter, but since the position of the catcher today is from the right side with no change in sight, a lefthanded hitting shortstop can fill that need.
The free agent that could be added to the lefthanded bats of Gallo and Hicks is Corey Seager at short, and if the Yanks also sign Anthony Rizzo, they have their four to give more balance to the lineup. The idea that righty relievers could come in throwing high heat to one batter after another hitting from the right side seemed to work against the Yankees in those tight games, and if there are four lefty swingers throughout the batting order, it changes the equation and that short right field porch doesn't hurt either. Seager brings a .300 batting average and the potential of giving you better power numbers at Yankee Stadium, and with all these facts in hand, there is no question that Seager should be the Yankees top free agent target.