James Hill, a defense attorney for Maddox, said he intends to fight the allegations against him and will enter a plea of not guilty should formal charges be filed.
Maddox, 33, began communicating with an undercover agent pretending to be an underage girl on April 28, an arrest report said. He expressed his intent to have sex with the girl even after she told him that she was 14, officials said.
Maddox agreed to meet the girl at a pre-arranged location, where he was arrested by law enforcement officers, authorities said.
He is charged with four felony counts, including traveling to meet after using a computer to solicit a child. He is being held in jail on a $300,000 bond.
Maddox played college ball for the University of Florida and was drafted by the Boston Red Sox in 2012. He made his major league debut with the team in 2017 after several years in the minors. He spent about three months on the Red Sox roster before heading back to the minors to recover from shoulder injuries. He was released from the team in 2019.