Officials fear the player may have defected, while the team was participating in the World Baseball Challenge.
Jim Swanson, the tournament organizer, said members of the Ciego De Avila Tigres noticed their teammate was not at their hotel and that tournament officials are working with the Cuban Baseball Federation and its delegation.
"We're working with the authorities and with the Cuban delegation to understand where that player might be, what might have happened," he said.
But Swanson expects the Cuban team will still put up a tough fight against Japan tonight.
"They're definitely in a good position to win their second straight world baseball challenge title," he said.
Cuba participated in the tournament in 2011, but this is the first time a player has gone missing.