Christian Pulisic was one of several notable absentees as Borussia Dortmund took to the pitches at the Estadio Municipal in Marbella on Friday.
The USA's 2017 Soccer Player of the Year is still suffering from a knock he took to his right shin a day earlier.
Watch: Christian Pulisic's December Goal of the Month winner
Leading scorer Pierre-Emerick Aubameyang, meanwhile, is not due in the Andalusian town until later on Friday evening after being granted permission to attend the AFCON Player of the Year awards ceremony in Accra, Ghana.
The Gabon striker finished third in the final vote behind Mohamed Salah (Liverpool/ Egypt) and Sadio Mane (Liverpool/ Senegal).
Dortmund face Bundesliga 2 leaders Fortuna Düsseldorf in a friendly on Saturday (kick-off: 17:00CET/16:00GMT).