Zenit have signed Wilmar Barrios from Boca Juniors to replace Leandro Paredes following the midfielder's sale to Paris Saint-Germain.
The Colombia international has signed a four-and-a-half-year deal with Zenit, who did not release details of the fee paid to Boca.
Instead, Barrios joins up with Zenit, who currently lead the Russian Premier League by one point ahead of second-place FC Krasnodar.
Barrios was a key part of the Boca side that reached the final of last year's Copa Libertadores, but he was sent off in extra time as River Plate triumphed in the second leg of the Superclasico at the Santiago Bernabeu.
Barrios is the latest player to be prised away from Boca after their Libertadores run.
Overall, Barrios has earned 17 caps with the Colombia national team, which includes three appearances at the World Cup.