Eisner is a member of the Washington, D.C. chapter of the Internet Baseball Writers Association. He has appeared on several local TV networks and is followed on Twitter by the likes of Peter Gammons, Christian Garcia, Ryan Mattheus, Denard Span and Ian Desmond.
He's also 8 years old.
His father, Adam Eisner, took his son, then 5 years old, to his first baseball game in 2009.
Adam didn't know what he was getting into, but Matt took an immediate liking to MLB -- and he did his homework, too.
"I learned a lot by watching ESPN, MLB Network and MASN [the local TV channel where Nats games are broadcasted], listening to WJFK [the local radio station where the games are broadcasted], and reading Sports Illustrated, Sports Illustrated Kids and other baseball books," Eisner said.
"In addition to watching the Nationals, I watch other teams play. I read player stats on the backs of baseball cards to get to learn about players I don't usually get to see play. I don't get to stay up to watch the end of the night games, so I watch reruns of the games and analysts on MLB Network talk about what happened in the games."
"Baseball is a sport that can be enjoyed on many levels," his father said, "but really appreciated when you learn the science and strategy of the game. I'm not saying that he is fully there yet, but he definitely has an understanding and appreciation of the sport that many people much older than him have not developed. Also, there is an orderliness to the game that really appeals to him. The fact that you can map out a game in progress in a scorebook and catalog it for future reference also appeals to his worldview.
"It is with this backdrop that we encouraged Matt to start writing about his passion. In truth, it began a little more like a bargaining chip, where his mom would allow him to watch a little more MLB Network if he would write a paragraph about what he learned on TV."
But that simple paragraph evolved into something much bigger than any of the Eisners could have imagined.
After opening the first iteration of Matt's Bats, a small blog whose readership consisted mainly of friends and family, Adam set up the now full-fledged website and a Twitter account for his son to help spread the word.
The rest, as they say, is history.
The blog has been a learning experience for the third grader.
"The blog is an opportunity to spend time with him working on his reading and writing skills," Adam Eisner said. "He thinks of each topic and does necessary research online, an important skill for kids to learn. Even the acts of typing and word processing are important to develop. We work with him very closely to edit his posts for spelling, grammar and punctuation. We also see his diction and sentence syntax improving by leaps and bounds. At first, we literally had to tell him that he could not use the word 'pizza' as an adjective like his friends do at school -- 'That diving catch by Ryan Zimmerman was pizzas!'"
It's also a way for Matt, who loves baseball and writing, to explore a career in the sport.
"I learned when I interviewed Amanda Comak, who writes about the Nationals for the Washington Times, that when you are a journalist, you cannot be a fan of the team you are covering because you just have to report the news without being biased," he explained. "I think it would be hard not to have a favorite team to root for. So I would like to be a color commentator."
He's already got a start -- on a tip from a TV commentator friend, he announces games as he watches them on TV.
Despite his new Internet following, Matt does his best to stay grounded.
"In the future, I hope to do more interviews, especially with Nationals players like Gio Gonzalez, Bryce Harper and Stephen Strasburg," he said. "I love getting new followers and retweets. I love it even more when it's players or celebrities who follow me or write to me.
"I want to keep having fun doing Matt's Bats. This is not about the publicity, it's about challenging myself to keep doing better and having fun while doing it."
Adam Eisner is just as grateful for the experience as his son.
"One of his readers expressed it well when he said, essentially, 'When I was 8, I collected baseball cards. Matt is collecting the actual players as Twitter followers and meeting and interacting with them online, and we get to watch it all happen,'" he said.