It's practically the natural law of baseball that almost every team needs more pitching at almost every time, given the position's high attrition rate. There's a more finite number of slots for offensive players, and this winter's robust trade market has impeded the free-agent market's invisible hand of matching hitters with lineup vacancies.
The Nationals and Phillies filled their centerfield holes via trades with the Twins. The Diamondbacks got their shortstop from the Reds, who in turn got their centerfielder from the Indians in a three-way deal. The Rays got their slugger of the future from the Royals and their shortstop from the Marlins.
The free-agent market for hitters is starting to look like a high school prom where there's an even number of boys and girls in the senior class, so everyone's going to pair up perfectly, until a few start inviting dates from other schools and opening the seemingly closed community. The symmetry is gone, and one wonders if everyone will get a chance to dance.
It's mid-December and nearly a week since the winter meetings concluded, yet many key players are unspoken for.