Port Vale interim manager Michael Brown said that defender Kjell Knops suffered a severe injury during the defeat to Rochdale.
Knops was stretchered off in the first-half after a lengthy delay and Brown told the media: “The ball goes into the box and Kjell goes to clear it and his knee snaps.
“I think it shocked the players – he was down for a long time with such a severe injury and we won’t be seeing him for a long time.
“It was a bad, sickening injury and it had an effect on some of the younger lads. It was very sad to see and took the wind out of our sails. Obviously being down to ten men as well made it very difficult.”