After weeks of speculation about his future at the network, Kevin Reilly confirmed Thursday that he is stepping down as entertainment chairman next month.

No successor was named, but there's been speculation that Fox Broadcasting COO Joe Earley will continue to take on more programming turf, as he already has during the past year. There's also been talk -- unconfirmed -- that FX Networks chief John Landgraf might assume some oversight of Fox Broadcasting programming.

For the time being, Reilly's lieutenants will report directly to Fox Networks Group chairman-CEO Peter Rice. Rice and Reilly sought to cast the decision as a mutual decision, but chatter about Reilly's tenure has been ongoing for some time and picked up after the network had mixed reviews for its upfront presentation earlier this month.

The shakeup at Fox comes at a moment when James Murdoch is exerting more influence over Fox's Hollywood operations, following his promotion to co-COO of 21st Century Fox alongside Chase Carey. Having a say in the key exec change at the Fox network will give Murdoch a prime chance to guide the network to its next iteration.

"21st Century Fox is a great company that has provided me with choice seats at the head table of pop culture over two very rewarding stints both at FBC and FX, and I am grateful to have benefitted from the leadership of Peter Rice, Chase Carey and Rupert Murdoch," Reilly said in announcing his departure. "Peter and I have been discussing this transition for a while, and now with a robust new slate of programming for next season and strength in the FBC ranks, it felt like the timing was as right as it could be. I couldn't be more thankful to my team - a group of creative, tireless and fun people whose fellowship I will miss."

Said Rice: "Kevin's undeniable creative gift and passion for talent have left an indelible mark on our company, and we're extremely grateful to him for his leadership, beginning with 'The Shield' and 'Nip/Tuck' at FX and continuing through 'Glee,' 'New Girl,' 'The Following,' 'Sleepy Hollow' and 'Brooklyn Nine-Nine' at Fox. Kevin and I have been discussing his desire for a new challenge for some time, so while everyone at the network will miss his enthusiasm for adventurous television, we all respect his decision and agreed that after the upfront presentation was the right time. I'm personally extremely grateful to Kevin for his partnership during the past five years and look forward to working with him again in the future."

Reilly joined Fox in 2007 from NBC, where he was pushed out of his entertainment prexy post during one of Jeff Zucker's re-engineering efforts at the Peacock. At first he was reunited with Peter Liguori, the exec that Reilly had worked with during his earlier tenure at FX. Liguori's role was assumed by Rice in 2009. Reilly came to Fox as entertainment president and was upped to chairman under Rice in 2012.

Fox's eight-year winning streak as the top network in adults 18-49 came to an end during the 2012-13 season, when it finished behind CBS. And in the just-concluded season, Fox managed to stay in second (this time behind NBC) but that was thanks to the Super Bowl and NFC Championship Game. In regular-program averages, Fox placed fourth this season -- down 23% year-over-year and showing declines on every night of the week. The Wednesday/Thursday music competition series "The X Factor" and "American Idol" both took big tumbles, with the former getting canceled and the latter falling out of the top 10 for the first time. Other key shows like "Glee," "New Girl" and "The Following" also saw meaningful declines.

Here is the memo Reilly sent to Fox staffers:

To my friends and colleagues:

I have decided to resign as Chairman of Entertainment at FBC, effective at the end of June.

While difficult decisions have to be made every day, none have weighed more heavily on me than this. The inspired FOX leadership, coupled with your commitment to excellence at FBC, has provided one of the most rewarding chapters in my life.

I love TV. Always have. Since my mother told me to stop sitting so close and watching so much.

I couldn't feel more fortunate to be afforded the opportunity to preside over a dynamic business, collaborate with the most creative people on the planet and drive culture. And also to be positioned at the nexus of change. It's a fascinating moment in time as the digital evolution brings about radical shifts in consumer behavior. And through it all, the art form of TV has never been stronger or the marketplace more robust.

As invigorating as all that is to be a part of, we all know the daily feeding of the network beast and early morning ritual of waking to an overnight report card does breed a certain type of mania. My first boss, Brandon Tartikoff, described presiding over a broadcast network as "the worst best job in the world." I remember coming up in the business and seeing how the grind turned some executives into grizzled cynics. And I vowed to never become that guy. I have always believed it's incumbent upon network brass to bring a wide-eyed optimism to the chairs they rent. Talent deserves that. And frankly, the jobs are just no fun otherwise. Staying fresh and looking forward is part of why I feel the timing is right for me to turn the page now.

As you, my colleagues, know all too well, I am rarely satisfied. But I hope you all also know that I am very proud of what we have accomplished together and of the exceptional entertainment we have helped bring to fruition. We put shows and songs at the top of the charts, we took home trophies, we got out ahead of defining and building and measuring the multi-platform universe and we re-wrote rules about how to develop, program and market TV. And I think some of the best is yet to come next season. It's been a satisfying blast.

Thanks for all,

Kevin

P.S. - Don't go back to pilot season!

2014 Variety Media, LLC, a subsidiary of Penske Business Media; Distributed by Tribune Content Agency, LLC