The 29-year-old was substituted in the 16th minute of Porto's league encounter after going down with a suspected adductor injury.
Head coach Francesco Farioli issues an injury update on the status of Sanusi and Jan Bednarek, who were both forced substitutions during the fixture.
"We have to assess both of them; Zaidu's looks like something very serious, and Jan seems to have twisted his knee. We'll see," said Farioli to reporters after the match.
Sanusi potentially could miss out on the upcoming 2027 African Cup of Nations qualifiers for Nigeria although further examinations will determine the timeframe for his return to action.
The left-back had started all five matches for Porto this season prior to his injury. He has made 159 appearances for the club, scoring eight goals and providing three assists.
Sanusi has also played 30 games for the Super Eagles.
