I was surprised he fell south so fast

Another from sports talk radio.  A sports columnist, Ron Cook, was commenting on Pittsburgh Pirates pitcher Joe Musgrove’s recent poor outings and did not expect them after his excellent start of the season.  It is a congruent conflation of “fall apart” and “go south”, both meaning to depreciate or drop in value.  If you fall south then does that mean you rise north?  A big thanks to John Kooser who heard this one and passed it on.