Scantlebury, England's most capped international, turned his ankle during practice and may also miss the national team's European Championship semi-final round games in Belarus on 25 February and against Israel in Manchester on the 28th.
Newcastle's coach, Craig Lynch, said: "Peter has ligament damage but we're not sure how serious yet. As for the England games, we'll have to see what the physio says and how Peter responds to treatment."
The Eagles 92-74 defeat in last week's first leg ended a 13-game unbeaten run. Lynch admits his team may have been too concerned to protect their record rather than restrict Towers' first leg lead.
"We tried to win the game rather than play smart and threw the ball away too many times," he said. "Tonight we have to be positive. The first half is very important in cutting back their lead so we can put pressure on in the second period."Reuse content