Gareth Ainsworth reckoned QPR paid the price for their commitment to him at Ipswich on Saturday.
Rangers lost 2-0 to the Tractor Boys to ruin the caretaker manager's unbeaten start in charge, and Ainsworth blamed the wholehearted effort of the side when they won 1-0 with 10 men against Birmingham last Tuesday.
He said: "Maybe, the lads were a bit leggy after having done all they could for me and the team against Birmingham.
"It's something we need to look at when we have another two games in five days."
Ainsworth's old team Cardiff are the visitors on Saturday - but the caretaker doesn't know if he will be in charge.
He said: "It's a day-by-day situation, and nothing's changed."