The former England midfielder was cast as a villain last summer for turning down the opportunity to help Hull by joining Celtic.
Despite a recent 40m takeover by the Allam family, his 50,000-a-week wages are still a huge burden on the club and he will be allowed to leave in the New Year transfer window if Hull can find a taker.
Bullard's goal, however, was cruel luck on the Blades who had got back on level terms after being 2-0 adrift at the interval.
The result extended Hull's unbeaten run to seven games and lifts the Tigers to within five points of the Championship play-off zone.
Defeat left the Blades, who are currently in the hands of caretaker manager John Carver, four points above the relegation zone.
Hull manager Nigel Pearson admitted it was 'nice' to have a player of Bullard's ability available again but shed no light on his future.
Commenting on the result, Pearson said: "It was a very good three points and that is what is important.
"We had a very tough first half of the season and we disappointed ourselves because we have given ourselves an awful lot to do. But we have looked a better outfit over the last seven games. There is a little bit more determination about us.
"It takes time to change things but hopefully we can go into the New Year with a bit more optimism," he added.
"It can be frustrating when you are on a good run and don't seem to be making any headway in the league but we have to concentrate on ourselves and gradually you do make an impact.
"Because of the start we have had there is very little margin for error and it would only take a lapse of a couple of games to be looking in the other direction again.
"We have two home games coming up now (against Reading and Leicester City) and both will be very tough.
"Because we are playing catch-up we can't afford to switch off at anytime."
Blades caretaker manager Carver will remain in charge for a minimum of two more games but the club are also in talks with several other candidates for the job – including Port Vale manager Micky Adams – and have been strongly linked with Doncaster Rovers' manager Sean O'Driscoll.
Carver said: "The club is in a process, we have seen that Sean O'Driscoll has been in the process, and we have seen that the club has got permission to speak to Micky Adams.
"That's all part of the process and I don't think what happened (against Hull) makes any difference in the process.
"It is difficult for me to start talking about wanting jobs," he added. "I have not had time to think about anything other than the next game.
"I have not got time to distract myself thinking about jobs here and there. If I am distracted I am not focused on the job.
"We have three or four games over Christmas and that is good for the players and me. I can concentrate on the next fixture without looking over my shoulder.
"The club will still go ahead with the process and come out with the answer that they want and what is right for the club and I will be 100 per cent behind the answer they give."
Assessing his side's performance yesterday, Carver said: "I was delighted with the character. No one has ever doubted the effort and commitment that the lads put in.
"Sometimes we have just lacked a little bit of quality but (against Hull) we showed a bit of quality although also a bit of naivety at the end.
"I thought there was only going to be one winner at the end because we had them under pressure. It was a sucker blow."
The Blades had been jeered off the field by home supporters at half-time but regained their backing thanks to the impressive fightback.
Carver said: "The crowd are going to be restless because of the situation we are in – we are not flying high at the top of the table, we have a fight on our hands.
"I asked the players if we could shut them up, could we stop them having a go and make them be patient? I tried to use it as a motivational tool at half-time and I thought it worked."
Blades defender Andy Taylor was stretchered off early on after a challenge by Hull captain Ian Ashbee.
Carver is anxiously awaiting news on the extent of the damage but he is unlikely to be involved in tomorrow's trip to Norwich City.
Hull left-back Kevin Kilbane was also taken to hospital after leaving the field with a nasty head wound.
Manager Pearson confirmed that talks are still on going over possible deals for Peterborough United striker Aaron McLean and Leicester striker Matty Fryatt.