Speaking of the news Town boss Joe Royle said the news could not come at a worse time when Chris Makin is ruled out and he also has injury worries over John McGreal and Georges Santos in central defence.
"It's a big blow and the last thing we needed right now. Fabian will be out for a month and it could be as long as six weeks." Royle explained on Tuesday afternoon.
"Fabian has been terrific for me from day one and we saw against Crewe, when he was suspended, how much we miss him. He has been exceptionally consistent since I came here.
"He seemed to be better after Saturday and we were thinking in terms of him being out for just one week, so this is a major setback."
Royle also admitted he may look into bringing a right back on loan whilst Wilnis is ruled out with injury, but instead he may turn to Jermaine Wright who formerly played in Wilnis role when he was suspended for the league game against Crewe.