The Super Eagles coach has invited the winger to watch Nigeria play Argentina in Abuja in June.
Sam, who plays for Bundesliga side Bayer Levekusen, was born to a German mother but his father comes from Lagos.
As he has not played for Germany at full international level, Sam can play for Nigeria if Fifa approves his nationality switch.
Siasia is hoping to persuade Sam to commit to the Super Eagles and play in the African Cup of Nations qualifying campaign.
"I already met him in Germany and he sounded very intelligent about his career," Siasia told BBC Sport. "Just like other young Nigerians who were born abroad we are hoping that with the new Fifa rule, he can change his mind to play for us."
The 23-year-old had been keen on playing for the Germany senior side before meeting Siasia last week.
The Nigeria coach is hoping that an invitation to watch the Super Eagles could help convince him to play for the West African country.
"We have extended an invitation to him and his family for the friendly against Argentina (1 June) and I hope after that he will understand he has a chance to prove himself as the Nations Cup qualifiers resumes then," Siasia explained.
"He has never been to Nigeria before, that's why we are bringing him and his family to the country for that friendly match.
"Hopefully, the country, football and what it's got to offer will help him in his decision making," said Siasia.
Source: BBC Sports
