How to validate in_place_edit updates

Can anyone enlighten me on how to make in_place_edit fields go through
validations that are defined in the model? For example, my customer
model has a “validates_numericality_of phone”, but when the
in_place_edit is done you can enter whatever you want. The field is
defined as a string in the DB. I can’t change the database schema, due
to other constraints, so I need a programmatic way to accomplish this.