Phil Sieben has made a return to Rot-Weiß Oberhausen after his departure from Norderstedt. In the previous season, he participated in 15 competitive matches for RWO before initially relocating back home during the summer. Sieben received training at VfL Lüneburg, SC Paderborn, and Schalke 04, and he played for SC Paderborn's second team. Additionally, he had two appearances in the second Bundesliga with Fortuna Düsseldorf and played for Roda Kerkrade in the second Dutch league. Dennis Lichtenwimmer-Conversano remarked on Sieben's talent and mentioned the challenge of integrating him into the adapted playing culture, as well as guiding his development.