Lots of obvious contending teams will get tossed out as potential landing spots for Polanco, but one to keep an eye on is the Pittsburgh Pirates.
Last year the Bucs were able to compete for most of the year before falling off, and they're in the market for a second baseman to help fill out the roster. The NL Central is wide open with the Brewers making a managerial change, the Cubs still rebuilding, and the Cardinals in limbo.
Adding Polanco could give Pittsburgh a solid bat in its lineup but also provide the clubhouse with veteran leadership to help usher in a new era. He might not single-handily take them over the top, but we've seen the sort of impact Polanco can have on a team with what he's done in Minnesota, and a team like the Pirates would be wise to get some of that magic to sprinkle around.
Pittsburgh also has a Top 10 farm system in the latest FanGraphs ranking, which means the Twins could get back a nice piece for the future to continue its youth movement. Part of the reason it makes sense to trade Polanco is the logjam of infielders about to hit the Majors, so adding a top prospect makes sense.
Minnesota could look to flip him for pitching depth as well, which seems to be a strategy for replacing Sonny Gray and Kenta Maeda this winter.