Andrey Arshavin fears the Russian team will 'collapse' if Guus Hiddink leaves his role to become Chelsea's full-time manager.
The Blues confirmed on Wednesday that Hiddink had replaced Luiz Felipe Scolari in the Stamford Bridge hot-seat on a deal until the end of the season.
Hiddink will continue in his role as Russia coach but Arsenal new boy Arshavin is worried the arrangement could change.
Arshavin does not believe Russia would be able to cope if Hiddink decides to quit the national side and take up a permanent position with Chelsea.
"For me, the most important thing is that Hiddink doesn't leave the Russian team," the former Zenit St Petersburg playmaker told Sport Express.
"If Guus was to quit, our side could just simply collapse without him. I don't see any realistic replacement for him.
"However, if he feels he has the strength to help Chelsea, then that's how it should be."
Hiddink guided Russia to the semi-finals of Euro 2008 and Arshavin expects him to be successful with Chelsea in the Premier League.
However, Arshavin admits he does not want Hiddink to do too well as Arsenal and Russia could both suffer.
He explained: "On one hand, I would like to wish Guus good luck, but on the other hand, Chelsea are now rivals.
"Also, I am worried that if everything goes well for Guus in London then he will stay with Chelsea for longer."