The 30-year-old attacking midfielder impressed for Las Palmas last season, scoring 10 goals in 28 La Liga appearances.
Boateng signed a three-year contract extension in May but the ex-Schalke man left the Canary Island club but mutual agreement on Wednesday.
In a statement, Las Palmas said: "The player's personal situation has precipitated his departure. Boateng will continue his sporting career in a place that will allow him to be closer to his family."
It now appears that place will be Frankfurt after the club tweeted a picture of Boateng undergoing a medical and promised more information to follow.
Eintracht begin their Bundesliga season away to Freiburg on Sunday.