Italian veteran Claudio Marchisio will make his debut for Saint Petersburg when they visit surprising Orenburg in the Russian Premier League this weekend.
The 32-year-old midfielder Marchisio, who played 55 times for Italy and won seven Serie A titles, joined the league leaders last Monday as a free agent.
With English defender John Terry deciding against joining Spartak Moscow, the Italian was the main big-name acquisition by Russian clubs during the international break.
"Marchisio has just arrived, he needs time to gain his top form," manager Sergei Semak was quoted as saying on the Zenit official site. "But we know his strength and we hope he will help us to restore the balance in midfield which was upset with (Christian) Noboa's injury.
Promoted Orenburg started the season strongly, and, even though they have earned only one point in their last two league matches, Semak insists he is taking them seriously in Sunday's game.
"Orenburg sit fifth after six matches. It's a solid result and I expect a hard clash on Sunday as they will likely try to show their best against the league leaders in front of their home crowd."
Spartak Moscow, two points behind in second place, are at home on Sunday against Akhmat Grozny, who lie 10th.
Spartak manager Massimo Carrera also insisted he was not expecting an easy ride and added that in the past his team have often stumbled when players returned from national teams.
"We need to take our opponents seriously regardless of their position in the table to avoid problems that we've often experienced in the past after the international breaks," Carrera told the Spartak press service.
"Spartak footballers looked impressive in the matches for their national teams. But for me it's even more important that none of them have been injured."
Reigning champions Lokomotiv, who have struggled this season, face a Moscow derby against Dynamo on Friday.
Lokomotiv lost their lost their last game, away to Krasnodar, and their next away match is their Champions League opener in Istanbul on Tuesday against Galatasaray.
Dynamo, in seventh, are a point and a place above Lokomotiv whose coach, Yury Syomin, said he was worried.
"We started this season poorly, while Dynamo look much more impressive than a year ago," he told Russian TV. "We have a very tough game ahead of us."
Fixtures (all times GMT)
Lokomotiv Moscow v Dynamo Moscow (1630)
Rubin Kazan v Yenisei Krasnoyarsk (1100), Ufa v CSKA Moscow (1330), Arsenal Tula v Samara (1600)
Orenburg v Zenit St Petersburg (1100), Anzhi Makhachkala v Krasnodar (1330), Spartak Moscow v Akhmat Grozny (1600)
Ural Yekaterinburg v Rostov (1430)