Burnley boss Sean Dyche disappointed with officials after 'red card' challenge leaves Johann Berg Gudmundsson facing a spell out injured
With Dyche's squad already down to the bare bones, the Iceland winger was stretchered off after a poor challenge from Sheffield United centre back Jack Robinson.
Referee Paul Tierney didn't even give a free kick, for what many felt was a red card offence, including Dyche, and the manager said: "We haven't got enough players, we know that, we've lost another one tonight in Johann - it's highly, highly improbable that's going to be a quick one, after the injury he sustained from a really poor tackle.
"Unfortunately there's not a lot in the pipeline, I don't know of anything that is, so it's going to be tough.
"I didn't see it back until half-time to be fair, at the moment of asking, our players thought it was a bad one, I didn't think it was as bad - I don't mind telling you that, I told Chris (Wilder), in my day, in your day, that was standard, but having seen it back at half-time, it was a really bad challenge and he should have been red carded."
Dyche added: "I did look at it at half-time to try and get my mind straight and see what kind of challenge it was, but it's a twist of his knee, and like I say, I think it's unlikely at this early stage it will be a matter of days, I'd be very surprised.
"He's been looking nice and sharp and it's another player down, and we haven't got a lot in the pipeline to my knowledge, so it's not helpful.
"We'll wait and see, he's settled down a bit now, but we'll have to give him 24 hours and make a decision on what the next steps are."
Dyche's players recovered from that blow, after losing an early goal as well, to come back to take the Carabao Cup tie to penalties, where they advanced.
Dyche said: "The marker on the game is just that challenge, the goal we could have maybe done better with, but I thought we defended very well overall, the performance was good, I was pleased with that, good to win through, but eventually you lose a very good player who's had a tough time with injuries and was looking really fit and well, to a needless challenge.
"I was amazed by some of the decisions tonight, it seems to be when VAR goes away, how does that work then? No crowds of course in the stadium, so that affects them, they're human beings, I get that, without that pressure of a crowd sometimes it changes things.
"But it was clear for the linesman, he's five yards away, the referee maybe different, the fourth official can see from where I am it doesn't look a good challenge.
"Times have changed, in my day, it would just have been a bad challenge, yellow card, but nowadays that's a red card."