It's only December 17th, but this offseason has already been mildly successful. The Yankees traded for a young, cost-controlled shortstop, reacquired Chase Headley to solidify the infield and ensure that there would be flexibility given injury, signed Andrew Miller to lock down the bullpen, acquired Chris Capuano to play the swing man, and signed Chris Young as a fourth outfielder. But of course, the team isn't done making moves.
The biggest area of need, to no one's surprise, is the starting rotation. Brian Cashman rightly stated that he "robbed Peter to pay Paul", so to speak, in acquiring Didi Gregorius in exchange for Shane Greene. Now the team has two open spots in the Opening Day rotation, and no one internally that could fill it. There is Adam Warren, David Phelps, and Bryan Mitchell, but I wouldn't let them touch a solidified rotation spot with a ten-foot pole. There are a few options on the free agent market, but they're all imperfect in their own way.
There is the top-tier of Max Scherzer and James Shields, and then it tapers off to: Aaron Harang, Jake Peavy, Ryan Vogelsong, Edinson Volquez, and Kyle Kendrick. That is either very expensive or incredibly underwhelming. There's always the possibility they just break the bank for Scherzer, but they would probably only have the payroll to add someone of an extremely low caliber and hope for a bounce back afterward. There is of course the trade market, but that would also require the Yankees to give up someone, and Cashman has not been wont to do that, unless it's for spare parts. Either way, this an area of obvious concern with quite a few imperfect but feasible options. The puzzle pieces will probably fit together in a month or so.
After that, the holes are more so cracks in the wall to fill. Another possible area of improvement is the bullpen. Even though a bullpen headlined by Andrew Miller and Dellin Betances is not desperate for improvement, there are certainly small ways to bulk it up. An interesting idea is to acquire a closer, which could be mildly successful given the options available: Jason Grilli, Sergio Romo, and Rafael Soriano, for example, are all available. I wouldn't totally be opposed to this if the team is confident he'd be serviceable; if so, then that would allow Joe Girardi to be flexible in usage with both Betances and Miller to effectively maximize their value. There's also the option of middle relief help, but that would probably be inconsequential and more worth using Warren, Phelps, and others.
And in terms of position players, everyone is mostly locked in to their position. The only thing I could see is the acquisition of a back up first baseman, but I would imagine the chance of that is slim considering the precarious position of Alex Rodriguez. They could opt to sign a non-roster invitee to roam the infield as a utility man, but we don't know yet. There's always Jose Pirela and Rob Refsnyder, too. But, there's always a need for depth on the bench, especially when the ranks can diminish quickly on an oft injured ball club.
To be honest, there aren't that many black holes. There is of course the rotation, but after that it's a bit more subjective. Cashman has always been good at throwing together utility pieces and decent bullpen arms, so that shouldn't be the largest concern. The larger concern is that much of the team's success next year relies upon bounce back years from players who frankly can't be replaced. There aren't too many more holes to fill, but hopefully the existing pieces still do their part.