This paper shows how to generate underactuated manipulators by substituting nonholonomic spherical pairs for (holonomic) spherical pairs in ordinary (i.e. not underactuated) manipulators. As a case study, an underactuated manipulator, previously proposed by one of the authors, is demonstrated to be generated, through this pair substitution from an inversion of the 6-3 fully parallel manipulator. Moreover, the kinetostatic analysis of this underactuated manipulator is reconsidered, and a simple and compact formulation is obtained. The results of this kinetostatic analysis can be used both in the design of the underactuated manipulator and in its control.