EXCLUSIVE: This would be considered a major loss for any agency as Mark Gordon is among the top nonwriting TV producers with several shows that have gone the distance, including ABC’s Grey’s Anatomy and Private Practice, CBS’ Criminal Minds and Lifetime’s Army Wives. Gordon had been with Chris Silbermann for more than a decade, first at BWCS and then at ICM, and Silbermann guided the producer as he built his Mark Gordon Co. from scratch into a several-hundred-million-dollar pod. The timing of Gordon’s departure is surprising. It comes on the heels of the breakout success of his latest series, Ray Donovan, which broke ratings records for Showtime this summer. It also comes at the height of selling season and in the midst of the Mark Gordon Co.’s big four-year deal at ABC Studios, which has two more years on it.