Andrus is a good fielder, he's speedy (37 steals in 2001), he hits for decent average (.286 last year, .275 for his career) and has a career OBP (.342) the Yankees can live with. He's probably still improving and best of all, he's signed through 2014, meaning -- barring a long-term deal from Texas -- he will become available just as the Yankees are faced with the big decision of whether or not to re-sign Jeter.
Cabrera is a decent average and on-base guy who can hit for power (16 HRs in 2012, 25 in 2011), but a below-average defensive shortstop who might be headed to second or third base. He also strikes out way too much. Like Andrus, he's signed through 2014.
Escobar had a good year average-wise (.293) in 2012, and was a demon on the bases (35 steals in 40 attempts), but has little or no power (five homers in 2012, 14 in four big league seasons). Like Andrus, he's an improving player, but unlike Andrus, he's under team control through 2015, and the Royals have options on him at reasonable prices ($3 million and $6.5 million, respectively, for 2016 and 2017). The Yanks would need to trade for him and he probably won’t come cheaply.
Castro has youth and tons of potential. The Cubs obviously think his best is yet to come because they have tied him up until 2019 with a seven-year, $60 million deal signed last August. He has hit at or close to .300 in all three of his big league seasons, has some pop (24 HRs the past two seasons) and boasts some speed (12 triples last year). The Yanks would have to put together a strong package to pry him loose.
A middle-of-the-road player who is at the high end of the age scale -- he will turn 29 next Monday and will be 33 by the time his current contract runs out at the end of 2016 -- Aybar might be worth a trade as a stopgap if the Yankees can’t get a younger option.
Ramirez can play shortstop or third base extremely well, but his once-great power and speed appear to be diminishing and he seems to be the kind of clubhouse headache the Yankees have sought to purge over the past few years. Coming out of a six-year, $70 million deal at the end of 2014, he will cost too much and be too old to be worth the risk.