[6] On the matchday 8, Frommann was given preference over regular goalkeeper Maximilian Reule in a match against Bayern Munich II and made his debut in professional football.

[7] The rest of the season, he was mostly a backup to Reule, as Sonnenhof Großaspach suffered relegation by finishing in the penultimate spot in the league table.

Upon his return to Freiburg, he was not a part of the club's future plans, and in early October 2020 his contract was terminated shortly before the transfer window was closed.

Liga club SV Meppen, valid until the summer of 2022, after regular keepers Luca Plogmann and Matthis Harsman had suffered injuries.

[11][12] Following his retirement, Frommann co-founded FUTURE GOAL alongside football coach and bank clerk Sven Oliver Gercke.