Barnes announced on his Facebook page on Friday that he is implementing an autograph policy that will allow his fans to get his signature, free of charge, in the offseason.
"Since I get so many requests for autographs, I bought a P.O. Box for all of you to send items for me to sign," Barnes wrote.
"I'm really excited to sign for everyone who's ever asked me for an autograph. I appreciate all the messages and replies I get on social media. This is my thank you to all of you and a token of my appreciation for not only supporting me as a player but as a person as well."
Barnes wrote that in order for fans to qualify for an autograph, they must write a handwritten letter explaining why they want an item signed and send a photo of them holding the item.
Fans, who are permitted only one autograph per person, also must include a self-addressed, stamped envelope for Barnes to return the item.
"My time is limited because of daily workouts, 'Games of Thrones,' 'House of Cards,' and video games," Barnes wrote. "Items will be sent back as soon as possible."