Manager Kevin Blackwell said: "Darius has done his ligaments, at least that's what we think. I just hope, please God, it's not as bad as it looks. He went to turn, his boot got stuck in the turf, and he went the other way.
"Darius went for some tests before the game and we're due to find out exactly what's wrong within 24 hours."
Henderson scored United's only goal at Pride Park last Saturday while he contributed to a finish in the Carling Cup at Huddersfield.