Four months after Oprah Winfrey seized the reins to Discovery Communications' most glamorous asset, the Oprah Winfrey Network, Peter Liguori announced Wednesday that he is leaving his post as Discovery's COO at the end of the year.

The departure of Liguori, a well-regarded programing executive who previously served as chairman of entertainment for Fox Broadcasting and CEO of the FX network, is not considered a huge blow to OWN or Discovery, at least in practical terms.

Liguori was hired as Discovery's No. 2 executive under president and CEO David Zaslav two years ago, and was charged with overseeing the launch of co-ventures OWN and The Hub. With those two channels launched, and Liguori marginalized from daily operations at OWN, Liguori's role going forward became uncertain. (Discovery said Wednesday that his position will be eliminated.)

He was already out of the day-to-day picture at OWN, said an individual familiar with Liguori's departure. This is just formalizing it.

However, the executive turmoil doesn't look good for Winfrey or her struggling network.

has no excuse now, the insider added. If the network isn't successful, it's all on her shoulders.

It was just in May that Liguori took the channel's interim CEO position, following the dismissal of another well-regarded programer, former MTV executive Christina Norman.

Two months later, with her syndicated talk show finally wrapped and off the air, Winfrey seized control of the channel, jointly launched by her Harpo Productions and Discovery, pushing Liguori aside.

She needed to make a pretty significant move, and that significant move was taking over, said an individual familiar with OWN's situation.

Liguori struck an amicable tone in his departure announcement Wednesday, calling his time at Discovery incredibly rewarding.

However, insiders say the marginalization privately irked Liguori, a Los Angeles-based TV programer/marketer who was already in an unfamiliar role, serving an largely administrative function while helping oversee the launch of Discovery's joint ventures, which included not only OWN, but kids channel The Hub, a partnership with toy giant Hasbro.

Meanwhile, ratings have hardly improved under Winfrey's more intimate watch of the joint venture, into which Discovery has poured more than $250 million so far.

In the third quarter, OWN averaged just 213,000 viewers in primetime, making it basic cable's 53rd most watched channel. Worse, women 25-54 -- the channel's key ad demographic -- make up just 35 percent of OWN's third-quarter prime-time audience.

In fact, that target demographic declined 11 percent to 74,000 for the quarter.

According to programing analysts, who wished to remain anonymous, the channel's non-fiction offerings, such as Oprah's Lifeclass are widely viewed in the television industry as unwatchable.

Harpo, he noted, now finds itself playing a different game, moving from broadcast syndication to basic cable. Instead of programing for the feedback-rich forum of myriad TV station groups and Indie channels, it's now creating shows in a vacuum, and having to fill an entire lineup in the process.

The shows are just so pontificating, the programing analyst said. You know that saying, 'A spoonful of sugar helps the medicine go down?' Well, all they're giving you is castor oil here.

Winfrey, he added, also made a big tactical mistake by failing to more effectively use her syndicated talk show as a launch platform for OWN before it departed the airwaves last spring.

Meanwhile, for his part, Liguori had been spending more and more time working back home in Los Angeles and away from Discovery's Silver Spring, Md., headquarters.

The exit from Discovery, insiders say, will afford him the ability to return to his more comfortable role in the scripted-programing realm.

He sort of got lost in the shuffle, an individual familiar with his situation noted. He's a good programer, and I'm sure he'll land somewhere. But at Discovery, with OWN and The Hub both launched, he had served his purpose.