I normally wouldn't share a rumor from Reddit as anything substantive, but the user NotPercyChuggs who posted this tip apparently divulged his/her source to the mods and convinced them of its legitimacy:
"Joe Mauer to announce retirement; press conference Monday"
I've never had much doubt that Mauer was going to hang 'em up, and with respect to the Twins' planning needs I presumed an announcement would be coming any day, so this aligns with my expectations, which is another reason I'm willing to lend it credibility. Stay tuned and we'll post any other news on the subject. Otherwise, we'll see what happens on Monday.