Albion, who impressed on Tuesday night as they earned a 0-0 draw at Chelsea, are seven points above the drop zone with six matches remaining.
Brighton defender Ben White will serve a one-match suspension following his red card in the midweek draw at Chelsea.
Forward Percy Tau could return to the squad after being absent at Stamford Bridge due to a tight hamstring.
Tariq Lamptey (hamstring) and Solly March (knee) remain out.
Scroll down and click through to see our predicted starting XI for Bramall Lane
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Brighton's Danny Welbeck will be assessed ahead of kick-off at Bramall Lane today
. Robert Sanchez
The Spanish stopper will continue his impressive run inbetween the sticks at Bramall Lane. A huge success story for Brighton this season
. Adam Webster
First match back after ankle injury at Chelsea and will be required to go again in defence as ben White is suspended for this one
5. Joel Veltman
A very consistent performer. Defensively sound and very safe in possession. Could play on the right of the defence at Sheffield United with Webster on the left.
6. Pascal Gross
Another senior player who has really stepped up to the challenge this season. Will likely feature on the right of the midfield today at Bramall Lane
7. Adam Lallana
Made a positive impact from the bench at Chelsea and should be back in the starting XI against Sheffield United. His class in the midfield has been key for Brighton in the second half of the season
8. Jakub Moder
Could be between Moder and Burn for a place on the left. I think the Polish international will just about get the nod for this one. His athleticism and ability to drive forward could prove useful