Collecting trading cards is exploding. Orioles and Nationals players collect them, too.

The visiting clubhouse at Nationals Park was nondescript on June 16. Royals players sat at their lockers. Others played cards. Then Bobby Witt Jr. stood, his silver turf shoes glistening as he strode across the room.

Each step served as a reminder of Witt’s interests coming to life.

Witt, one of Major League Baseball’s elite shortstops, has been collecting baseball cards since he was a kid. His mom would take him to any store — a Target, a grocery store or a local card shop — that had packs.

This month, Baltimore-based apparel company Under Armour and Witt announced the launch of his first player-exclusive footwear called “Dream Pull,” paying homage to Witt’s love of baseball and card collecting. The shoe features holographic finishes, chrome accents and, for the first time, his logo on the tongue of the cleat.

The turf and cleat versions of the shoe are available at Under Armour and Dick’s Sporting Goods. Any customer who purchases a cleat or shoe will receive an exclusive Panini card in the box.

“A lot of the things I’ve been doing have kind of been related to cards, just trying to grow with how the cards are growing, too, how big everything is getting,” Witt said in an interview with The Banner. “It kind of has that sapphire look, like there’s cards that are sapphire cards. ... It’s really cool, just to kind of see where it goes from here.”

Witt’s fascination with cards developed in an era when collectibles became prominent, in particular among MLB players. Fanatics founder Michael Rubin said in a CNBC interview in May that his company was set to earn $5 billion in the organization’s collectibles division alone. Many players exchange bats and jerseys to hang in their man caves. Now they’re collecting baseball cards, too.

Witt looked through his old cards during the COVID-19 pandemic and learned through eBay how valuable they were. From there, he became ingrained in card culture, buying, selling and grading cards. Signing his first Bowman cards, a player’s earliest official trading cards, only added to his passion.

Now Witt has an Instagram account dedicated to card collecting that helps him facilitate trades with fellow collectors.

Witt isn’t alone in his passion. Players on the Orioles and Nationals have joined in on the hobby, though their reasons vary.

After he was drafted, Orioles infielder Jackson Holliday agreed to a five-year deal with Topps to sign cards. He was scheduled to sign cards last week in Seattle.

Only recently did he start collecting cards himself after being influenced by infielder Jeremiah Jackson, who primarily collects baseball cards. Jackson’s prized possessions are a Shohei Ohtani rookie card and a Prince Fielder autographed card. Shortstop Gunnar Henderson collects Star Wars cards, while Rico Garcia searches for Michael Jordan ones.

Holliday doesn’t know how good he is at collecting cards but enjoys the camaraderie with teammates. He was among a group of players that went to Fells Point card shop Paradise Card Breaks ahead of the team’s series against the Mariners.

“The way they explained it when I was drafted was COVID started the market for all this, especially for draft guys signing card deals,” Holliday said. “Ever since COVID, this has kind of blown back up.”

One day, after watching a show on Netflix about trading cards, Garcia asked his dad if he had any old cards. Eddie Garcia did — some Jordan cards, which turned out not to be valued highly.

Rico Garcia directed his attention toward graded cards to better track their value, and during this year’s spring training the right-handed reliever put in more time tracking down cards he would like to add to his collection.

“It’s a pretty good collection, I would say,” Garcia said, adding that he picked up a Jordan rookie card in Bellevue, Washington, on Wednesday.

“A lot of people nowadays, they base it off the performance [of the player], and that’ll fluctuate the value of it,” Garcia said. “But MJ, Kobe [Bryant], [Tom] Brady, their values only go up because they’re done. They don’t have to prove anything. Their values only go up, and I was like, if I’m going to collect, I would want it to go up in value. So I decided just to stick with Jordans to make it easier, not spending a whole bunch of money on other guys.”

But Garcia also has a collection he saves for personal keepsakes. He collects some baseball cards and has those players sign them when they visit Camden Yards or Garcia is on the road.

“I’ll have it for my home and have a nice setup for memories,” he said. “The baseball side is all personal, just to have memories.”

Nationals catcher Drew Millas, like Witt, was bored during the pandemic, started looking through old cards and fell in love with the hobby as he bought more.

Millas views card collecting as an investment opportunity. The first card he bought was for $200; he sold it for $2,500. Now Millas runs a platform with Marlins reliever Pete Fairbanks to sell cards on eBay, though their names aren’t immediately recognizable to buyers.

“Some people do,” Millas joked when asked if people know who they are. “But in the card game, the Pokémon card game, people have zero idea who Pete Fairbanks and Drew Millas are.”

The cards available on the market can meet a variety of avenues and interests. Millas, for example, collects Pokémon cards in addition to football cards; he’s buying up Bo Nix cards because he believes the quarterback is due for a breakout.

Nationals outfielder Dylan Crews collects UFC cards and SpongeBob SquarePants cards, in addition to baseball cards. And, of course, he collects his own.

“It’s kind of crazy how you sign it, it’s probably the last time you’ll ever see it, and then you ship them off, and then they’re out in the world,” he said. “Then you’re just hoping that it surfaces, and hopefully you get that card. That’s the other thrill part of it, too.”

Crews started building his portfolio during his first major league spring training in 2024. One of the first packs he opened contained a 1-of-1 Ilia Topuria Superfractor. (Translation: The only copy of that particular card that exists.)

Crews had no idea who Topuria was until he did research. Topuria is the No. 1 lightweight fighter in the world. From there, Crews was fully invested in UFC cards.

His most valuable card, in addition to his Topuria card, is a Pristine 10 Mickey Mouse short print card graded by Beckett. (Translation: Pristine 10 means the centering, surface, corners and edges of the card are in the best possible condition and it earns a black label on top of the holder. A short print means a card is printed in significantly lower quantities than standard base cards in the same set. There are only three of Crews’ Mickey Mouse cards in existence, and he has one.)

Crews gets his friends to help him track down his own cards online. He typically buys them, though occasionally he’s engaged in trading for them. The next card he wants? His own Topps Garbage Pail Kids card, called “Cruisin’ Crews,” that is SpongeBob-themed.

And then there’s Zack Littell, who sat by his locker Tuesday and fit cards into a blue binder. He has three sets of binders: navy, yellow and black. The navy one contains Littell’s favorite cards. The black holds his stock cards. The yellow holds his prized possessions: the ones with players’ signatures.

Littell started collecting last season in Tampa Bay. He opens a few packs every month but doesn’t seek out specific cards. Rather, he gets signatures from current and former teammates, as well as opposing players.

Littell, a nine-year major league vet who has played for six teams, typically knows at least one player in the clubhouse of most teams. He’ll sometimes have friends take cards into the opposing clubhouse. If not, he’ll have a clubhouse attendant ask. He said the practice is becoming more common among big leaguers.

He used to be nervous sending cards over. He didn’t want players to think he was trying to sell their signatures. Yet players have been overwhelmingly open to signing.

His hope is to keep the cards for his kids. Littell joked that his 2-year-old son typically bends the cards. His 4-year-old son is just starting to understand baseball and develop a list of favorite players. In the years and decades that follow, both will have unique mementos from Dad’s career.

“This is just for me, and it’s cool,” he said. “I’ve got a nice little collection at this point of signed cards that I think will be really cool for my kids to look back on.”

Banner Orioles reporter Andy Kostka contributed to this article.