While the team did everything to try and get in, Hart knows that it would have stretched the squad even more.
Playing in the Europa means a lot of Thursday-Sunday weeks, which can be very difficult for teams who cannot rotate sufficiently.
"I've done it for years but I've done it in a bigger squad," Hart said to the Lancashire Telegraph about the Europa League.
"We've got to be honest with ourselves, we've got a squad where one injury or one knock in certain positions and we're in trouble.
"Burnley have proved before me that they can handle the Premier League and now it's our time to show that."