I hadn't seen this when it was first reported by the San Francisco Chronicle, but apparently Tony La Russa is not a fan of the guy who made a fake Twitter page about him and has filed a lawsuit. The filing prompted Twitter to immediately remove the fake page, but the suit remains pending.
I have no idea what the law is here, though I presume that it falls closer to the land of cybersquatting than it does identity theft or anything like that. Whoever put up the fake page, however, probably didn't realize that (a) Tony La Russa is a lawyer; and (b) Tony La Russa doesn't appear to have any sense of humor whatsoever.
In other words, the lawsuit probably shouldn't have come as much of a surprise.
(thanks to Levi Stahl for the heads up)