One might think that after a show is picked up by a network and placed on its fall schedule, all it has to do is shoot additional episodes, right? Wrong. After the pilot is picked up, shows usually go through what has been dubbed the "tinkering" stage, where changes are made to cast and/or script.

Among this year's changes, Grant Show is expected to leave the NBC drama "UC: Undercover," Breckin Meyer is getting a new ex-girlfriend on "Inside Schwartz" and the American half of The WB's U.K.-set "Off Centre" is being recast, according to Variety.

In addition, returning shows are starting to make small casting additions for the fall: such as former "Star Trek: Voyager" regular Jeri Ryan joining the cast of FOX's "Boston Public."

Show ("Melrose Place") stars as "UC's" team leader in the pilot on NBC's new high-profile Sunday action drama. His role is expected to be changed to guest-star status as producers work out the possibility of a new story arc that may lead to Show's character exiting the series altogether after a few episodes.

On "Off Centre," producers have decided to find a new American roommate for series star Sean Maguire, recasting a role played by Josh Radnor in the pilot.