Alberto Comazzi has left Swindon Town by mutual consent just seven months into a two-year contract.
The Italian defender, 32, arrived in the summer on a free transfer but only played five games for the Robins.
"I'm disappointed because when he came here I thought he could be an important part of the team," manager Paolo di Canio told BBC Wiltshire.
"But it has been tough for him at this level - we didn't know that before we signed him."
Di Canio continued: "I recognised my mistake at the beginning, not because I don't have knowledge in football, but because I didn't know about this level.
"I'm sure he could play two leagues above this league - but in Italy."