"The Tonight Show" host Jay Leno called NBC executives "snakes" in Monday's monologue. Reuters

Two high-level sources in the television industry have claimed to The Hollywood Reporter that Jay Leno, host of "The Tonight Show," will retire in 2014 from that position, which he’s held since he succeeded Johnny Carson in 1994.

Leno’s show regularly beats the competition in attracting late-night audiences, but NBC may ask the long-time host to step aside before the show loses more ground to ABC’s Jimmy Kimmel, who has been gaining viewers at the expense of "The Tonight Show." Both Leno and David Letterman, his rival at CBS, are signed through the 2013-2014 TV season, and both have indicated in the past that either of them would be unlikely to step away from the small screen before the other.

“We do not speculate on rumor,” one of Leno’s representatives told THR, but the article's sources pointed to "Late Night" host Jimmy Fallon as Leno’s successor for the 11:35 p.m. slot because of his proven ability to attract younger viewers.

“The more time Jimmy Kimmel is in that slot, the more the young audience goes that way, the harder it is for Jimmy [Fallon] to keep that audience,” the source told THR.

“Kimmel has done extremely well,” another network higher-up said. “Jay wins overall, but on any given night, it’s neck-and-neck in 18-49. I understand where they might have fear and also feel that they own the solution [in Fallon].”

Leno has struggled to mend his reputation since his first retirement went awry in 2010. After ceding "Tonight Show" hosting duties to previous "Late Night" host Conan O’Brien, Leno and NBC executives -- former president Jeff Zucker, in particular -- ousted O’Brien in one of the most epic public relations disasters in recent television history. Chief among the critics was Kimmel, who directly questioned a visibly uncomfortable Leno about the situation on his own show.

Kimmel reiterated his position during an interview with Playboy earlier this month, in which he accused Leno of losing audiences because of his glossy, aloof persona.

“I have a filter mechanism in my head every night when I put together the monolog for our show: If I can imagine Jay Leno telling a joke, then I won’t do it, even if it’s a good joke,” Kimmel said. “I always feel bad if I hurt anybody’s feelings, but I don’t believe Jay Leno has actual feelings, and he doesn’t seem to be worried about other people’s feelings.”