The striker has been out of action since September 21 when he suffered a hip injury against Norwich City.
However, the 22-year-old was named on the bench for Belgium's World Cup qualifier against Wales on Tuesday night.
"He must have been fit enough to go on the bench, or they wouldn't have done that," Lambert told BBC Sport.
"He's been in dialogue with our medical people. He's doing well and felt good.
"He was training Sunday and Monday with the national team. We trust Christian to come back and then see how he feels and judge from there."
Benteke is Villa's top scorer this season with five goals in all competitions.