Rob Lowe, "pigskin prognosticator?" That might just be the actor's latest role, after the Brat Pack-er turned Parks and Recreation star tweeted to his 250,000 followers this week that superstar Indianapolis Colts quarterback Peyton Manning, who missed this season with a neck injury, is retiring at age 35. Manning's reps aren't saying a word. Others close to the four-time NFL MVP are refuting Lowe's claims, but the implausibly youthful actor is sticking to his story. Here's what you should know:

Remind me: Why is Peyton Manning a big deal?
One of the NFL's best players for more than a decade, he's counted among the greatest quarterbacks of all time. He's been selected for the Pro Bowl 11 times, won the league's MVP award four times, and took home a Super Bowl trophy in 2007. His family is football royalty: Manning's father was an NFL quarterback, as is his younger brother Eli, who won a Super Bowl with the New York Giants in 2008. Peyton sat out the entire 2011 season with a neck injury, and the typically consistent Colts went 2-14 without him. Now the Colts have the top pick in the NFL draft, prompting massive speculation over whether they'll select a new QB to replace the ailing Manning.

OK. So what did Lowe say?
The firestorm began Wednesday afternoon when Lowe tweeted, "Hearing my fave, #18 Peyton Manning will not return to #NFL. Wow. #Colts." He added fuel to the fire with a follow-up tweet to NFL commentator Rich Eisen: "My people are saying Manning will retire today. What do you hear?"

Why would anyone take this seriously?
For starters, the West Wing star was the first person that Colts owner Jim Irsay followed when he joined Twitter. The two are friends, says Chris Mortensen at ESPN, so Lowe could conceivably have been privy to insider information. And Lowe has relentlessly insisted the news is true, even in the face of ridicule. Another Lowe follow-up tweet from Wednesday, however, opened the door to the possibility of error: "#Colts fans, let's hope my info is wrong. Don't like being wrong, but this time… I'm hoping."

What do Manning's people say?
Manning's father Archie "laughed," telling ESPN's Chris Mortensen, "He ain't retiring. I think he would've told me." When contacted by the NFL Network, Manning's agent said "this is the first he's heard about it." Manning himself has yet to weigh in on Rob Lowe's intrepid reporting. As for Irsay, he responded hours later on Twitter by mocking Lowe: "My sources tell me Rob will star in an epic remake of Deep Throat with aging porn stars and 4 finger circus clowns!" But tellingly, says Robert Klemko at USA Today, Irsay teased Lowe without "denying the actor's tweet."

And the saga continues?
So far. Lowe still refuses to back down. During an appearance Thursday on Ellen, he called Twitter a "powerful, powerful medium." When host Ellen DeGeneres asked Lowe to identify the source of his information, he demurred: "Ellen, I could tell you, but I'd have to kill you."

So… is Manning retiring?
It would be pretty hard to believe that "the guy who played Billy Hicks in St. Elmo's Fire" really scooped "the biggest story in the NFL," says Steve Politi at the New Jersey Star-Ledger. But remember, Manning recently had three neck surgeries, and the Colts are cleaning house, firing their head coach and general manager. That's "a pretty convincing argument for retirement," says James LeBeau at Crave. Either way, says Bob Kravitz at The Indianapolis Star, this days-long "is it true?" debate is a teachable moment. "From here on out, we need to agree Twitter is not the place where you write what you hear is going on; it's where you write what you know is going on."

Sources: Crave, Entertainment Weekly, ESPN, Indianapolis Star (2),, Star-Ledger, TV Guide, Twitter (2), USA Today, Wash. Post