CBS has reduced the episode order for a police procedural that has been a staple on the network. Writing on TVLine.com, Michael Ausiello reports that the network cut the order for “CSI” to 18 episodes, down from 22.

The show is in its 15th season, and this is the first time the drama will have produced less than a full season of episodes, the story notes.

“I’m told the decision was more about inventory than ratings,” Ausiello writes. “In addition to spinoff ‘CSI: Cyber,’ which is slated to assume ‘CSI’s’ Sunday-at-10 perch later this season, CBS also has Vince Gilligan’s ‘Battle Creek’ and a seventh season of ‘The Mentalist’ waiting in the wings.”

He adds, “‘CSI’s’ move to Sundays at 10/9c has produced decent results: Although the show is down double-digits from its Season 14 average (when it aired Wednesdays at 10), it’s maintaining the time period’s year-ago average in viewers and adults 18-49.”