New Era and Topps team up for first-of-its-kind baseball card set

For the first time, you may open a pack of baseball cards and find one that contains a swatch from a cap worn by Bryce Harper. Or Buster Posey. Or Andrew McCutchen. Or Marcus Stroman.

New Era Cap and Topps announced on Friday a first-of-its-kind baseball card set that will appeal to both cap lovers and baseball-card collectors. They’re making a limited-edition set of cards that feature the nine New Era ambassadors in MLB, with even-tougher to pull cap relic cards and player autographs. The cap relics are limited to 99 of each player.

Here’s the catch: You can’t get these at your neighborhood card shop or Target. They’re only available at the cap shop.

Starting Friday, when you buy a New Era cap at one of the 800 participating Lids locations around the U.S., you get a special pack of the Topps/New Era cards. The cards come four to a pack and the only players included are the New Era ambarassdors: Harper, Posey, McCutchen, Stroman, Josh Donaldson, Jacob deGrom, Kyle Schwarber, Dellin Betances and Joc Pederson.

Since these are limited in nature, they won’t be around long. So, if you’ve got to have some, don’t wait until the World Series.

More MLB coverage from Yahoo Sports: