Neymar was carried off grimacing in agony after a heavy challenge from Colombia defender Juan Camillo Zuniga toward the end of Brazil’s 2-1 win in Fortaleza.
The 22-year-old was whisked to hospital for tests after the incident and Scolari said afterwards he was now doubtful to recover in time.
“He was kneed in the lower back,” Scolari said.
“We don’t have the exact information but I can guarantee it won’t be easy for him to recover based on what the doctor told us and the pain he is in.
“It will be very difficult for him to play.”
Any injury to Neymar would be a massive blow to Brazil’s hopes of beating Germany and advancing to the final.
The Barcelona superstar has been integral to Brazil’s World Cup campaign so far, scoring four goals en route to the last four.
Read more here Capital Sports