Alexander Mostovoi has recovered from his thigh injury in time to play in Russia's opening World Cup game against Tunisia, but a decision on his participation is to be delayed until the day of the game.
"Whether I can play against Tunisia will only be known on the day of the game," Mostovoi said on Russian television.
"It all depends on [my] general condition."
The 33-year-old play-maker missed Russia's 3-0 win over J-League side Shimizu S-Pulse on Thursday, their first warm-up match since arriving.
Celta Vigo star Mostovoi had been training alone in a bid to shake off the injury to his right hamstring.
Russia coach Oleg Romantsev said Mostovoi would play in the opening group H game against Tunisia on 5 June in Kobe if he is fit.
And this was confirmed after the warm-up match by assistant coach Mikhail Gershkovich.
Gershkovich said: "Mostovoi is on his way back to fitness with the help of some training.
"There are still five days to go before the match."
Mostovoi's creative ability is key to Russia's hopes of progressing to the second round.
The Celta Vigo midfielder has battled with a series of injuries over the past two years and sustained the latest injury in a friendly against Yugoslavia on 19 May.
"It was very unpleasant to get an injury on the eve of a serious tournament especially as it will be the last of my career," Mostovois said.
"It's the third time I've received an injury on the eve of a big tournament and that can't help but worry me.
Ruslan Pimenov, Yegor Titov and Dmitry Khokhlov scored the goals in Russia's win.
But without rested captain Viktor Onopko at the centre of the defence and defensive midfielder Alexei Smertin, their rearguard was often exposed by Shimizu's lively attack in the first half.
Gershkovich was not too displeased, though, and said the game had been a useful exercise.
"Always when you leave out such a player it changes things on the pitch.
"Today the players tried out some different roles. That was our plan.
"I must say as a whole it was satisfactory."