The 25-year-old Brazilian star is widely regarded as one of the most lethal forwards in all of Russia, and has attracted interest from a host of clubs across Europe.
Reds boss Kenny Dalglish has been alerted to Welliton's availability as he looks to strengthen his attacking options at Anfield in the January transfer window, following confirmation of Luis Suarez's eight-game ban.
Liverpool have identified Welliton as a player who would add more firepower to a side that has struggled for goals in the first half of the season.
However, Dalglish will face competition for the South American's signature from Arsenal boss Arsene Wenger, who is also looking to bring a striker to the Emirates Stadium.
The Gunners will be without the likes of Gervinho and Marouane Chamakh during the African Cup of Nations, and Wenger is also keen to ease the pressure on captain Robin Van Persie.
Thierry Henry is set to return on a two-month loan deal during the MLS close-season, but Welliton is seen as a long-term solution to Arsenal's problematic striker situation.
Spartak Moscow are desperate to keep their prolific forward but would consider offers in the region of £7million.
However, Liverpool and Arsenal will need to act quickly if they are to sign Welliton, after reports in Russia suggested that both Fiorentina and Dortmund have entered the race for his signature.