Ghana international Kevin-Prince Boateng has rejoined AC Milan on a free transfer.
"Kevin-Prince Boateng has signed a contract until 30 June, 2016," the club said in a statement.
The midfielder, 28, was suspended indefinitely by Bundesliga team Schalke in May and had been training with the Italians since September.
A move to Sporting Lisbon fell though last summer and he stayed on Schalke's books until his release in December.
German side Schalke suspended Boateng after a 2-0 defeat at Cologne, saying there was "a mutual lack of trust" between club and player.
Boateng first joined Milan on loan from Genoa in 2010, made the move permanent in 2011 and last played for them in August 2013.
AC Milan, who host Bologna at the San Siro on Wednesday, are sixth in Serie A, eight points behind leaders Inter Milan.