The 32-year-old stopper has found opportunities limited under new manager Ancelotti and may have to quit in search of regular football.
Casillas was nominated for European Footballer of the Year award in 2008 and in 2012 he was voted into the UEFA team of the year for the sixth time in a row.
Casillas is considered one of the finest goalkeepers of his generation and became the most capped keeper of all time in the UEFA Champions League in 2010 and the most capped player of all time for the Spanish national team in 2011.
Arsene Wenger reportedly had the option to swoop for the keeper back in August but decided against the move. Arsenal are enjoying life at the top of the table and Wenger may stick with Szczesny although the keeper has come under some criticism in the past.
Manchester City could be the more likely destination with the questionable form of Joe Hart over the past year. Casillas would be the ideal replacement with an impressive record in the Champions League and a wealth of experience.
With Qualifying for the later stages of the Champions League high on the list of priorities at Manchester City Casillas experience would be a good addition and would see him join with his fellow Spanish international team mates Jesus Navas, David Silva and Alvaro Negredo.
Jesus Navas has stated that ?We all know the great keeper that Iker is and the importance he has within the team. At city we have great keepers, but Iker would be a great addition.?
Source: DSG
Source: DSG