PITTSBURGH -- Corey Seager thought it was a joke. Across the Los Angeles Dodgers clubhouse, Kenley Jansen viewed it as something “unique.”

When Chicago Cubs shortstop Addison Russell asked those two All-Stars -- and many others around the league -- to autograph the back of his Pokémon cards, he knew he would get some puzzled reactions.

And he most certainly did.

Yes, Russell is sending clubhouse attendants to opposing locker rooms armed with Pokémon cards for some of Russell’s favorite players to sign.

Not just any player is worthy of signing a Pokémon card for Addison Russell's collection. It needs to be a player the Cubs shortstop admires -- and one who matches the traits of the Pokémon character on the card being autographed. Courtesy of Jesse Rogers

“I started collecting this offseason because my cousins, nieces and nephews all started collecting, so I wanted to find a way to relate with them,” Russell said with a big smile. “Get on that level with them.

“I’ve signed a lot of baseball cards of myself, and I just thought it would be cool if professional athletes would sign Pokémon cards. I started collecting them more, and now I’m asking guys to sign them.”

It began with his own team in spring training. Russell brought binders of laminated Pokémon cards with him to Arizona and started asking his teammates to sign them. With quizzical looks, they happily obliged.

“I used to collect the cards growing up,” National League MVP Kris Bryant said. “My neighbors back home collect them. I bought them a bunch of packs. So it’s funny, I get to spring training and Addy has this big ol' sheet of Pokémon cards. I was like, ‘What are you doing?’

“I loved it. I love everything about Addy. He’s a big kid.”

Inside a custom binder with his picture on the front sits Addison Russell's unique Pokémon card collection, sure to be the envy of kids -- and baseball fans -- everywhere. Courtesy of Jesse Rogers

So far, no one has turned Russell down, and there is a method to his madness. He doesn’t just pick the cards randomly. He’s looking for a card that fits the player’s game or personality.

“If there are flame balls on them, I’ll get a closer like Kenley Jansen to sign,” Russell said. “I got him to sign when [the Dodgers] were at Wrigley Field. I think he signed my 'Enflamed' card.”

“It was unique, man, and I was like, ‘OK, so what is he trying to do?’" Jansen said of the unusual request. "They asked for Pokémon [to be signed], and that meant he might like Pokémon, one of his favorite things. I think it was pretty awesome.”

Russell can appreciate the hesitation some players might have getting something different than the usual baseballs, bats and cards put in front them to sign. Pokémon? It’s definitely an extraordinary ask.

“I honestly thought it was a joke,” Seager said. “But no, that’s his thing; and that’s cool that he found his niche and what he likes to do. More power to him.

"It’s going to catch some people off guard.”

So far, Russell has “about 25 signatures” from teams the Cubs have played, beginning with exhibition games in Houston at the end of spring training. He got Carlos Correa, Alex Bregman and American League batting champ Jose Altuve to sign cards during that series.

“A flying-type dragon card because he’s aggressive and I like his style of play,” Russell said of Altuve.

A few days later, he got Jonathan Villar and pitcher Corey Knebel of the Milwaukee Brewers to add their signatures to his card collection.

“Knebel was like, ‘Really, bro? Pokémon cards?” Russell recalled, laughing.

The Pokémon requests have an added benefit for Russell, who is just 23 years old and pretty quiet as compared with others in the Cubs' clubhouse.

“They say it’s a little different, but what do you expect from the youngest guy on the Cubs?” Russell asked rhetorically. “When I do play against them on the field, they’re like, ‘Really, Pokémon cards, man?’ And I just tell them I appreciate them signing it. Kind of sparks a conversation.”

A couple of Russell’s teammates wondered what he’s going to do with the signed cards. "What’s the endgame?" one asked, jokingly.

"I'm going to keep doing it. I have some badass Pokémon cards that I need signed." Addison Russell

“My cousins are waiting to check out the collection after the year is over,” Russell said. “That’s the plan -- maybe even give them to my son. I really don’t want to sell them, but I’m down to trade some Pokémon if people want.”

And who knows, maybe Russell’s idea will spark a new idea across the league.

"I watched Pokémon a little bit. I was more of a Dragon Ball Z type of guy. I was watching more Dragon Ball Z growing up. So I get it,” Jansen said of Russell’s hobby. “Pokémon is his stuff, and everybody has their own unique way. I think it’s awesome, man, the way you see him doing it. I want to see how his creation is going to come out. I want to see how it looks at the end of the day when he has everybody’s signature.”

So who’s next on the autograph list? Even Russell doesn’t know, because the timing has to be right to ask a player the Cubs are facing, and he wants to pick the right card when the mood strikes.

“I’m going to keep doing it,” he said. “I have some badass Pokémon cards that I need signed.”

ESPN.com's Doug Padilla contributed to this story.