EXCLUSIVE: I have learned that Warner Horizon EVP Craig Erwich will be leaving his post atop Warner Bros TV’s cable/alternative division. I hear Erwich opted not to renew his contract and will stay on until his current deal is up in March. Erwich was the No. 2 programming executive at Fox when WBTV president Peter Roth — for whom Erwich had previously worked at Stephen J. Cannell Prods. — brought him over to build a cable and reality unit. At the time, WBTV had a cable hit in The Closer and an unscripted one with ABC’s The Bachelor but no one to spearhead that part of the business for the studio. Over the past six years, Erwich oversaw Warner Horizon’s transformation into a major cable player claiming the top-rated series on two networks — Rizzoli & Isles on TNT and Pretty Little Liars on ABC Family, where the studio also has spinoff series Ravenswood. Additionally, Warner Horizon is behind Lomgmire, A&E’s most watched original scripted series ever; Dallas on TNT; Sullivan & Son and Ground Floor on TBS; and it produced Greg Berlanti’s Political Animals for USA Network. On the unscripted side, during Erwich’s tenure Warner Horizon landed its biggest hit with NBC’s The Voice and launched such series as the long-running Randy Jackson Presents America’s Best Dance Crew on MTV, Oh Sit! on the CW and has the upcoming Famous In 12 on the CW and Copycat on MTV. Last August, the unscripted portion of Warner Horizon’s portfolio was shifted to Mike Darnell, who joined WBTV as President, Warner Bros. Unscripted and Alternative Television. With WBTV’s business structure evolving, Warner Horizon’s start-up phase over and the fully grown division in good shape, I hear Erwich felt it was time to move on. It is unclear what he would do next but sources indicate it would likely be another executive position for the well-liked exec, who spent 12 years at Fox before his six-year stint at Warner Horizon.