"We have good players, but we have a problem in the defensive line. Our right-back is a [naturalized] Brazilian [Mario Fernandes]. We have no Russian footballers in defense. [Alexey and Vasily] Berezutski refused [to play], [Sergei] Ignashevich was forced to return to the team. So we don't have defenders at all. That's why I think our weakest line is the defense," Tikhonov said in an interview on YouTube Wednesday.

Ignashevich, who will turn 39 in July, came out of international retirement to replace injured Rubin Kazan defender Ruslan Kambolov after Russia had also lost Spartak Moscow's Georgi Dzhikiya and CSKA Moscow's Viktor Vasin to injuries.

The 2018 FIFA World Cup will be held between June 14 and July 15 at 12 stadiums across 11 Russian cities. The hosts will face Saudi Arabia in Moscow on June 14 before playing Egypt in St. Petersburg on June 19 and taking on Uruguay in Samara on June 25 in their Group A matches.