According to a report by Sponichi, the four Cuba players currently in Japan with permission from the Cuba (Frederich Cepeda, Yulieski Gourriel, Alfredo Despaigne, and Hector Mendoza) will probably return next season. However, deals will have to be renegotiated, which could mean players signing with different teams in 2015.
The article goes on to explain that the players are considered government employees with the Ministry of Sports. As such, teams in Japan have to go through the ministry to sign a player -- the ministry can provide a list of possible candidates based on a list of needs, or teams can check players during scheduled tryouts in Cuba.
Players are limited to one-year deals based on government policy with foreign currency. Cuba is also interested in establishing connections with as many teams as possible.
Twenty percent of the player's salary reportedly goes to the government. While Cuba went along with many of the requests made by teams this year, that could change next season with players going to the highest bidder.
Source: Sponichi 8/19/2014