Murphy, a younger brother of former Florida big man Erik Murphy, told ESPN.com that he intends to transfer to the Gators.
"I really appreciate the experience at Duke, playing for a Hall of Fame coach in Mike Krzyzewski," Murphy told ESPN.com. "I learned a lot as a player and a person.
"I've gotten a chance to know Coach [Billy] Donovan and the program. I think it's a great fit for me to continue my career. I think they can help me develop as a player -- and that I can help them a lot as well."
The 6-foot-8 redshirt sophomore also considered Rhode Island, Providence and Northeastern.
Murphy redshirted his freshman year after suffering a concussion in the preseason. He played sparingly last season, and with the abundance of wings already in the program and the addition of Justise Winslow and Grayson Allen next year, he decided to continue his college career elsewhere.
Murphy played in five games this season and averaged one point and one rebound.
Erik Murphy struggled in his first two seasons at Florida before thriving in the final two. He was taken in the second round of the NBA draft this past June and is a rookie with the Chicago Bulls.
It also be interesting to see if the addition of Alex Murphy puts the Gators in a solid position to land the youngest Murphy, Tomas, a 6-7 freshman who is sure to attract attention from elite programs as he matures as a player.