Dean Smith claimed his Walsall side were lacking in confidence following their 4-1 home defeat to struggling Scunthorpe.
Scunthorpe took the lead after 13 minutes when defender Niall Canavan headed in Mark Duffy's corner. Duffy tapped in the second after 30 minutes when Walsall goalkeeper David Grof could only block Karl Hawley's shot.
A minute from half-time midfielder Prutton was red carded for a tackle on Adam Chambers, but shortly into the second half Canavan headed in number three from another Duffy corner. Leon Clarke then burst through to lob the keeper for the fourth before Will Grigg netted a consolation for Walsall.
Smith, whose team were without three key players through injury, said: "It's no excuse. I won't lay the blame on that. We are on a winless run at the moment and lacking a little bit of confidence, and in a young group that happens.
"There are two ways to go now - either sink or swim, and we have to get ourselves together and put it right. We lost a game here three or four weeks ago and the players were cheered off - now they were booed off.
"We are trying all the time to get new people in, and this result may force the issue. The last couple of games have not been up to the standard we need."