Rubin signed 22-year-old midfielder Leon Musaev from Russian Premier Liga champions Zenit St. Petersburg. The deal is for five years, while Zenit have a first refusal buyback clause. Musaev will wear the number 38 shirt for Rubin.

St. Petersburg native Musaev has played a defensive midfielder and central midfielder for Zenit at academy and youth team level, before at professional level for Zenit-II and and the full senior side. 

He made his RPL debut on 14 April 2019 against Anzhi playing 21 matches for the main team, including two Champions League matches against Lazio and Brugge. He has played 10 matches for Zenit and Zenit-II in various competitions this season, having twice been crowned champion of Russia (2019, 2020), as well as winning the Russian Cup (2020) and Russian Super Cup (2020).