Mario Pasalic will spend the upcoming season on loan at Serie A side Atalanta.
The 23-year-old moved to Stamford Bridge in 2014 from Hajduk Split and has represented Croatia at senior level.
Pasalic enjoyed a productive season on loan at Spartak Moscow in 2017/18, making 28 appearances and featuring in both the Champions League and Europa League. The midfielder has previous experience in Serie A after being loaned to AC Milan in 2016/17.
Having played the second half of our friendly win over Perth Glory on Monday, he now heads back to the Italian top flight to continue his development with Atalanta.
Nathan has returned to his homeland for a season-long loan.
The 22-year-old Brazilian midfielder, who has previously played in the Netherlands and France, and scored against both Benfica and Porto when with Belenenses for the second half of last season, has moved to Atletico Mineiro.