To replace ousted NBC Entertainment president Kevin Reilly, NBC yesterday turned to both an insider and an outsider to help pull the network out of fourth place.

Reveille Productions head Ben Silverman and NBC Universal Television West Coast president Marc Graboff were named co-chairmen of NBC Entertainment and of the NBC Universal Television Studio, days after word leaked that NBC was giving Reilly the boot.

Though nominally both men will be responsible for NBC’s daytime, late-night and most importantly, primetime schedules, Silverman will deal with the creative side while Graboff will handle the business side.

Reilly did not have oversight of the TV studio, which has produced hits like “House” for other networks. Now, however, NUTS will primarily focus on providing NBC with programming.

The shakeup came two weeks to the day after Reilly introduced NBC’s new fall schedule to advertisers, who were not pleased with his conservative approach and sci fi-focused new programs.

Though NBC Universal president Jeff Zucker, whose frosty relationship with Reilly was well known, insisted yesterday that no changes were planned to the fall schedule, there will likely be a few tweaks, perhaps on oft-criticized and long-sliding Thursday night.

There’s not enough time for a major overhaul, with the upfront expected to break soon and just over three months before the new season. The real test for the newly hired duo will be what midseason changes they make, including new programs, and what they do next year.

NBC is desperate to crawl out of the basement after three yeas of finishing last among adults 18-49, following years in which it owned that demographic with hits like “Seinfeld,” “Friends” and “ER.”

But during Zucker’s tenure as entertainment president, the network failed to find worthy successors to those programs, and its ratings have slumped despite airing critical hits such as “The Office,” “My Name is Earl” and “Friday Night Lights.”

Now Silverman and Graboff must maintain NBC’s reputation for such quality programming while continuing to attract upscale viewers and improving ratings.

The two come from very different backgrounds. Silverman is a former William Morris agent turned reality show producer who has brought a number of international hits to the U.S.

His reality successes include USA Network’s “Nashville Star” and NBC’s “The Restaurant,” but he may be best known for Reveille’s smart repurposing of foreign shows.

Reveille’s “Ugly Betty” and “The Office,” two of the most lauded new comedies on broadcast the past few years, were acquired from abroad. Silverman also helped launch “Who Wants to be a Millionaire,” based on the British game show, which became a huge hit for ABC nearly a decade ago.

Silverman, who has long admired former NBC president Brandon Tartikoff, pioneered the now-common product placements in reality shows several years ago with “Restaurant.”

He’s also been named one of People magazine’s most eligible bachelors.

Meanwhile, Graboff is a lawyer who’s close with Zucker and has been with the network since 1997. He was a CBS vice president prior to that, dealing mainly with business. He also was a partner at two Los Angeles law firms before entering television.