It’s Always Sunny In Philadelphia is the only one of what FX president John Landgraf called the “four cornerstones” of FX (The Shield, Rescue Me, Nip/Tuck and Sunny) that is still on the air. The comedy has already been renewed for a ninth season, and it will likely won’t be the last. “There is a high likelihood for a 10th season,” Landgraf said during the FX portion of TCA this morning. “Whether it goes beyond that depends on whether the people who created the show want to go and whether the audience still wants to watch. But there will definitely be one more year, probably two.”

Landgraf also shed light on FX’s scheduling plans for the back 90 episodes of Charlie Sheen’s Anger Management. “It will stay on the air with no interruption for two years, basically 45 episodes a year,” Landgraf said. That means that, save for major holidays and sports pre-emptions, there will be an original of Anger Management on Thursday night for two years, starting with the Season 2  premiere January 17. The biggest change made following the initial 10 episodes was the addition of Martin Sheen as Charlie Sheen’s father for a multi-generational dimension on the series.

Landgraf also was asked to to comment on the high showrunner turnover at AMC, including flagship The Walking Dead, which has parted ways with two showrunners while remaining a mega hit. “We’ve never fired a showrunner,” Landgraf said. “These shows are very personal; you can’t ‘plug and play.’ These are 90-hour movies. The author needs to complete the journey… What would The Shield have been had (creator) Shawn Ryan not written the final season?” As for The Walking Dead, “AMC managed to make a successful transition from creator Fran Darabont to Glen Mazzara,” Landgraf said. “It remains to be seen if they can do it again.”