Exit could leave space for the Russian in David Moyes' first team, however
The South African's contract runs out at the end of this season and he has been consistently linked with moves away from Goodison Park, with Tottenham said to be particularly interested in securing his services.
Goal.com UK exclusively revealed on Thursday that Siphiwe Tshabalala is being lined up as a replacement for his international team-mate.
A January sale represents the only chance David Moyes has to be able to cash in on the playmaker, although it would signal bad news for an Everton team that are running short on goals and struggling to make any headway in escaping the clutches of the relegation zone.
But Bilyaletdinov is wary about the opportunities that could arise for him should Pienaar leave.
"He's a great player and if he goes out in January it'll be a very bad thing for Everton. But we've still got other people to replace him," he told Sky Sports.
Despite playing some typically attractive football, Everton have found themselves floundering in the bottom half of the Premier League table. Bilyaletdinov credits their lowly position to bad luck.
He said: "We haven't had enough luck yet because we haven't won many games. I think Everton is the unluckiest team this season. That's why it's happening."