29-year-old Soares is out of contract in a year and has been made available for transfer by Porto.
Domenico Tedesco, the head coach of Spartak, has appreciated Soares’ qualities since his time in charge of Schalke.
Knowing Porto’s financial situation and Soares’ availability, Tedesco has asked the Russian club to make an effort to sign him.
If the €10m bid is confirmed, it will be the best offer Porto have received for their Brazilian striker.
Porto want €15m for Soares but are likely to accept the highest offer made.
Competition for Spartak
Shanghai SIPG will lose former Porto man Hulk when his contract expires this year and Tiquinho could replace him.
Tiquinho has been with Porto for four seasons and has an impressive return of 62 goals in 131 games.