Burnley could be without Jack Cork for the rest of the season, and skipper Ben Mee a big doubt - boss Sean Dyche
And skipper Ben Mee could also face a race to be fit for the last five games.
Cork suffered an ankle problem in the win at Crystal Palace on Monday night, while Mee saw a run of 70-successive Premier League starts ended by a thigh injury.
Cork could require surgery, and boss Sean Dyche said: "Ben has got a thigh strain - a pretty good one, so I don't think it's going to be a quick turnaround.
"Corky has a reasonably serious ankle injury, which is unfortunate.
"He is probably going to need something doing so probably he is out for this immediate spell of games, possibly for the remaining games.
"Not ideal, but we've had that since we came back."
Asked whether Cork would need surgery, Dyche added: "We're waiting on that but there is a chance, yes. It is looking likely."
Dyche's squad was boosted, however, with the return of Chris Wood, Johann Berg Gudmundsson and Robbie Brady, and although Burnley were legged back by a late Sheffield United equaliser, he would have taken seven points from the last nine available.
He said: "Absolutely. Really proud of the players. We would definitely have taken the points we had.
"I thought it was a tight affair, two competitive groups going at it the best they could.
"The wind was really powerful and it was difficult for both teams, and we are stretched at the minute.
"You ask for a competitive performance and to get something from the game, and you do get greedy. We had a couple of golden chances, particularly Dwight’s which would have seen the game through."
Burnley remain two points behind the Blades, who are eighth - which could mean European football, and Dyche noted: "People keep putting that on us. It was never the aim of the season. The aim was to stay in the Premier League. The second aim is to finish as high up the league as possible.
"We have our second-highest ever points at this stage, so we're not going to be overly-critical of the players, that's for sure.
"The players are working their maximum with very few bodies.
"The message is to be competitive and work our best and see where that takes us.
"We don’t have the group we were hoping to have, a few getting back to some form of fitness, but obviously we missed Corky and Ben Mee as well.
"The main thing is the competitive edge."