 Complete the following phrase:  Despite the co-ownership deal being renewed in June 2013, Juventus bought back Castiglia on 21 August 2013 for 350,000 in order to finalize another transfer for Castiiglia. On 2 September 2013 he joined Serie B outfit Empoli on a season-long loan agreement. With 19 appearances in the league, Castiglia helped the club gain promotion back to Serie A for the first time since 