[2] On 8 December he played his first game as a professional, starting in a 2–2 away draw against Real Jaén in the round of 32 of the Copa del Rey (eventual 4–2 aggregate win).
[3] Germán first appeared in La Liga on 6 April 2014, taking the place of suspended Kiko Casilla in a 4–1 loss at Sevilla FC.
[4] In January 2015, after losing his backup position to another youth graduate, Pau López, he was loaned to Segunda División club Racing de Santander until June.
[9] Two years later, he joined fellow third-tier UD Ibiza, agreeing to a contract until 30 June 2020 with the option for an additional season.
[10] On 1 July 2023, after suffering second-division relegation, Germán signed a two-year deal with Deportivo de La Coruña in the Primera Federación.