Grab the bottom of the rudder and pull back and down a bit to see if
the hinges are worn. The rudder pedal springs hold the rudder forward
and the slop isn't readily evident during a normal preflight. See if
you can wiggle the bellcrank in the rudder, or if there's any
deformation of the metal that it's attached to. Some nervous pilots
are in the habit of standing on the pedals with tense leg muscles,
putting a lot of strain on the bottom end of the rudder. Some people
have their airplanes tied down outside in strong winds and the rudder
gets bashed against the stops, beating things up.

Dan