Kaka left off Madrid Supercopa squad
The 30-year-old Brazilian midfielder was a surprise omission for the first leg at Camp Nou.
Kaka has failed to make an impact since joining Madrid from AC Milan in a $92 million transfer three years ago. He struggled with injuries at Madrid and has failed to secure a regular starting role in two seasons under Mourinho, with the Portuguese coach preferring Mesut Oezil and Angel Di Maria in attack.
Mourinho also left defender Ricardo Carvalho and Nuri Sahin out.