Sven Goran Eriksson admitted Leicester's play-off hopes had effectively been extinguished following the 3-2 defeat to Nottingham Forest on Friday.
Marcus Tudgay broke the deadlock for Forest before Matt Oakley quickly drew the Foxes level.
Leicester again responded well after falling 2-1 behind to Robert Earnshaw's goal, with Darius Vassell equalising just a minute later.
However, Paul McKenna secured the victory for Forest with a late strike that squirmed through the grasp of goalkeeper Chris Weale.
Any chance of making the play-offs appear to have ended as the Foxes are now six points shy of Forest with just nine points to play for.
And Eriksson said: "It's frustrating because once again away from home we have played good football but conceded three goals.
"We did very well to come back twice quickly but again it has finished the way it has too many times this season.
"We are playing well but we are conceding too many goals and too easily. The opposition does not have to work hard to score against us and it must change.
"I'm afraid that is the end of our play-off hopes and we will know for sure by Monday evening.
"Chris Weale apologised to the players in the dressing room but it doesn't help us get a point.
"But it can happen to anyone."
Eriksson acknowledged there is work to be done over the summer to challenge for the top of the table next year and the plans are already under way.
He said: "We have already started to think about next season and we will know where we belong.
"At the moment we belong in mid-table which is a shame. It is a tough league and if you want to get promotion what we have done is not good enough.
"But it is not English to give up so we will try and win our remaining games."