Nigel Adkins is calling for the fans to be 'part of the team' during Saturday's encounter with Wigan Athletic at Bramall Lane.
United enter the clash in ninth position in Sky Bet League One, ten points behind the Latics, who are in fourth spot, but the Blades boss is wanting the home faithful to be 'United together'.
Looking ahead, he remarked: "We know the fans are frustrated with the lack of transfer activity and our position in the table, we are too, but there is still a possibility of us achieving our aim this season, which is promotion back to the Championship.
"This Club has a long-term ambition to be back in the Premier League but we are a long way away from that at this moment in time and we are trying to take small steps to get this Club back where it belongs.
"But despite their frustrations, we need them to be part of the team, backing the players to the hilt in the remaining 18 matches of the season, because if we are United together our chances of success are greater.
"At the final whistle the supporters will rightly vent their opinions whether that be good or bad, that's the beauty of football, but during the game being negative and getting on the players backs won't help and doesn't help anyone."
The Gaffer added: "From top to bottom, we all share the same, one common goal and that's to be promoted now, this season and we have to believe it will happen, if we think negatively we will achieve nothing."