Ebanks-Blake sustained the problem during Wolves' Carling Cup win at Northampton on Tuesday night after scoring the second of his two goals.
It was the former Plymouth player's first start of the campaign after playing second fiddle to Steven Fletcher and Kevin Doyle for the opening two Barclays Premier League games.
Wolves boss Mick McCarthy confirmed: "The injury is worse than we first thought.
"Sylvan has damaged his medial ligament and you are looking at him being out for a month."
Meanwhile, McCarthy says he is unlikely to bring in any fresh faces before the transfer window closes next week.
McCarthy said: "It is unlikely that anyone else will be coming here before the window shuts.
"I repeat, I am happy with the squad I've got."
McCarthy intimated he is likely to keep faith with the side which won against Fulham last weekend for Saturday's derby at Aston Villa.
Source: PA
Source: PA