Rangers have already completed six summer signings.
The 19-year-old midfielder was a key member of Newcaastle Under-23's Premier League 2 campaign last season, making 14 appearances under reserve team coach Ben Dawson.
However, despite being highly-rated by The Toon's coaching staff, he failed to earn a run out in the senior team and was forced to make do with a place in the second string.
Sangare posted a picture of himself in a Rangers top on Instagram, though he later explained that the shirt was for his "lil brother" and that "nothing has changed".
Rangers have a strong connection with Newcastle, after Toon owner Mike Ashley bought a stake in The Gers worth 8.92% in 2014. But he sold those shares in 2017.
It saw Newcastle youngsters Haris Vuckic, Gael Bigirimana, Remi Streete, Shane Ferguson and Kevin Mbabu all go on loan at Ibrox in January 2015.
James Tavernier also began his career at Newcastle, and such a connection could see Rangers do business with Rafa Benitez's side. However, Sangare has explained why he wore the shirt, leaving fans with no second thoughts.