Via NFLShop.com

Even though he’s still months away from taking his first professional snap, Robert Griffin III just continues to be a beacon of admiration for football fans far and wide. The untested rookie’s latest achievement: Topping the sales charts for jersey sales.

Griffin’s No. 10 jersey was the best-selling in May and the third-hottest item since April 1, D.C. Sports Bog reported yesterday. The more amazing feat though: Rookie jerseys only went on sale April 26. In that truncated span, Griffin has been a better seller of football memorabilia than Peyton Manning, Tim Tebow or even this year’s top NFL Draft pick, Andrew Luck.

A replica jersey made by Nike retails for $99.99 on NFLShop.com, with the authentic articles, manufactured by Reebok, going for $149.99. (The replicas come ready-made with Griffin’s name and number; the real things require added customization.)

Still, scaling the merchandise charts isn’t exactly a new feat for a future Redskins quarterback. Redskins fans tend to be a little excitable when it comes to the gear. As Sports Bog points out, it was just two years ago that Donovan McNabb’s Redskins jersey was the second best-selling.

But Griffin’s jersey is notable for more than just the exciting playmaker who will don it on the field. It’s also the first NFL jersey to feature a Roman numeral on the back next to the player’s name, thanks to a recent change to league rules allowing players to include generational designations. Of course, an ESPN blogger earlier this month thinks that including the “III” on the jersey is just another way for Griffin to extend his nickname in a very lucrative way:

So why is the Roman numeral on his jersey? Presumably because it’s part of Griffin’s personal brand. And that’s not the only kind of branding at work here, because the Roman numeral III can also be viewed as three stripes—which happens to be the visual signature of adidas, which signed Griffin to a big endorsement contract back in February. In fact, Uni Watch suspects Griffin chose adidas over Nike specifically in large part because of the potential marketing synergies between the Roman numeral and the stripes. He’s the perfect foil for the trefoil. Think that sounds far-fetched? Consider this: Everyone else refers to Griffin as RG3, but adidas commercials refer to him as rgIII.

So, whether you’re into genealogy or sports marketing or so excited to see Griffin play that you’ll drop your cash on pre-season merchandise, it appears there are plenty of excuses to buy one of Griffin’s jersey.

And the new kid won’t be the only Redskin taking advantage of the NFL’s easing on generational markers. Roy Helu will be adding “Jr.” to his jersey this year, just as he wore it in colllege.