The Cubs’ Addison Russell celebrates his game-winning, three-run homer against the Brewers on Wednesday. (Kamil Krzaczynski/Associated Press)

There are three things you should know about the Cubs’ star shortstop, Addison Russell: He is only 23. He is very good at baseball. And he just invented everyone’s favorite new sports tradition.

According to a recent ESPN story by Jesse Rodgers, Russell is on a mission to have his favorite fellow MLB players sign Pokémon cards that match their playing styles and personalities.

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

Makes sense. What about Astros second baseman Jose Altuve?

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

Got it.

His reasons for signing Pokémon cards — rather than, say, bats, balls and other traditional baseball memorabilia — is actually quite sweet. From the ESPN story:

“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.”

You’re probably thinking: “Is this the weirdest and/or greatest athlete hobby of all time?” It’s tough to say. Becoming a professional athlete and competing at the highest levels of a sport requires an intense amount of focus and obsession. Sometimes that manifests itself in interesting hobbies and obsessions, including those that might seem a bit nerdy. 

Last year, Seattle Seahawks linebacker Cassius Marsh had $20,000 worth of “Magic: The Gathering” trading cards stolen from his car.

“It’s not even the money. I really enjoy playing the game,” he told the Seattle Times. “To me, that’s what I do to get my mind off things sometimes. You know how people zone out sometimes? That’s how I zone out. It’s hurtful because those are one things I really care about.”

Marsh offered two free home game tickets for their safe return. Thankfully, the card company sent him a care package for his troubles.

A 2015 Wall Street Journal story detailed the Green Bay Packers’ obsession with the strategy game Settlers of Catan, which was reportedly introduced to the team by tackle David Bakhtiari.

“I was just trying to play some music, some Pearl Jam, and [Bakhtiari] wouldn’t let me,” former backup quarterback Matt Flynn told the Journal. “He wanted to hear the players talk and strategize. He was very serious. They take it to a different level.”

Way back in 2011, former NFL punter Chris Kluwe gave an interview with World of Warcraft fan site Wowhead.com, in which he describes how he got into the game and which other massive multiplayer online games (MMOs) he plays. To be completely honest, it’s a little hard to understand some of the back and forth if you don’t play the games, but he seems very into it.

“I’m no stranger to MMO’s . . . as I started with Ultima Online, moved on to Everquest, then Asheron’s Call, Jumpgate, Anarchy Online, DaoC, etc. etc.,” he said. “It’s fair to say that I’ve played about 90 [percent] of the MMO’s that have come out in the U.S.”

And, recently, it was revealed that Angels slugger Mike Trout once convinced a former coach’s son to purchase $1,500(!!!) worth of weapons for the online mobile video game “Clash of Clans,” which I did not know people actually bought.

For what it’s worth, Russell’s new hobby might have an expiration date.

“My cousins are waiting to check out the collection after the year is over,” he told ESPN. “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.”

In the meantime, if he’s looking for a new obsession, we’re sure it won’t be hard to find.