Double-A Reading righthander Kyle Drabek, generally regarded as the Phillies' best pitching prospect, will not be called up after roster limits are expanded Tuesday.

In fact, the team announced Sunday that he has been shut down for the remainder of the season.

The announcement stressed that Drabek is not injured but that this was instead a "proactive" move to protect a 21-year-old who has already thrown 158 innings between Class A Clearwater and Reading this season (61.2 at Clearwater and 96.1 at Reading).

He has been placed on the temporary inactive list.

Drabek is not scheduled to participate in the Arizona Fall League or Forida Instructional League this offseason.