Santos, who was born in Almada, Portugal
but holds a British passport after moving to England aged one, is set to report for a training camp with the Portugal Under-21s next month.
I am Chairman of the Portuguese Association of Obstetric Nurses (APEO), having been a male midwife since 1989, I was head of the midwives and nurses team in the Maternal-Fetal Medicine Service at the Hospital Garcia de Orta, in Almada, Portugal
, from 1991 to 1997 and worked most recently in the delivery room at the Hospital Sao Bernardo, in Setubal, Portugal.
The 19-year-old - who was born in Almada, Portugal
but holds a British passport after moving to England as a toddler - made 24 appearances at the heart of the Posh defence as the club finished ninth in League One.