Unless the Yanks think they can sneak into the postseason (I think they may be too far out by the trade deadline) and really make some noise once they get there, I think they should react with long-term implications in mind. Jeter is on his way out. Tex has massively underwhelmed and not exactly stayed healthy. Youk isn't exactly very young. And A-Rod....well, no explanation needed there.
They are an aging, injury-prone team, and really need another infusion of talented youth, a la Jeter, Posada, Bernie Williams, etc. in the mid 90s. I'm not familiar with their farm, so I do not know who is waiting in the wings, but if the opportunity to trade Tex/A-Rod or anyone else with little left to offer the Yanks (Vernon Wells to a contender lacking a bat, for instance), NYY should take the opportunity to get younger and sign Cano to a long-term deal.