Noel Whelan is concerned about the mental impact that Leeds United's 4-3 home defeat to Millwall could have on the Whites players.
Leeds had a first half to forget at Elland Road as skipper Liam Cooper was sent off for a reckless challenge and the Whites headed in 2-0 down at the break.
Remarkably ten-man Leeds rallied after the interval and even went 3-2 ahead thanks to goals from Pierre-Michel Lasogga (two) and Kemar Roofe.
But the Lions made their man advantage count and levelled with three minutes left before then winning the contest in injury time through a Jed Wallace effort.
Whelan thinks losing in such a matter late on left the Leeds players completely drained and says they will feel low.
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And while he knows they can recover physically over the next ten days, the former Leeds forward is concerned about the mental aspect of a defeat which has knocked the Yorkshire giants down to tenth in the Championship.
"I think today is going to take a lot out of them, I really do", Whelan said on BBC Radio Leeds.
"Not so much physically, but more mentally.
"They will be absolutely drained and they should feel lower than a snake's belly.
"So I hope they reflect on this and take the positives from the second half and what it takes to win football matches."
Leeds are now heading for a week-long warm weather training break to Spain.
