The rumours are not surprising, Holmes was Charlton’s stand out player and top scorer in a disappointing season.
Also, he wants an improved contract at The Valley, and played for Blades manager, Chris Wilder, at Northampton.
Wilder signed MK Dons wideman, Samir Carruthers, in January. Carruthers was a player Karl Robinson wanted, and he has hardly featured at Bramall Lane.
So it easy to see how speculation with tenuous links to a swap deal started, but is there any substance to it?
Wilder failed to persuade Holmes to make the move north twelve months ago, so has sufficient changed to make the Essex based winger change his mind?
United will have a bigger budget in the Championship, so money could be a factor, but it is questionable whether Holmes would be a regular starter.
His season at The Valley was his first at League One level, and the Championship would be another step up.
Holmes is an exciting player to watch, he takes players on, scores goals, but the weakness in his game is his final ball.
He delivered a peach of a cross for Josh Magennis to head home against Swindon in the last game of the season at The Valley. But he needs to do that on a more regular basis if he is to thrive at a higher level.
It is also possible the story could have been leaked by Holmes’ agent in an attempt to secure his client a better deal at The Valley.
Possible rather than probable seems to be the correct assessment at the moment.
Jason Euell’s Under-23 side were cruelly eliminated by Hull in the semi-final of the Development League Two national play-offs at The Valley on Monday evening.
A dull game ended 0-0 after 90 minutes, but exploded into life during extra-time.
The Tigers raced into a two goal lead, but two goals in a minute just before the break from Brandon Hanlan and Karlan Ahearne-Grant levelled things up.
Regan Charles-Cook gave Charlton the lead four minutes after the interval, only for Hull to level deep into stoppage time.
Charles-Cook missed the first penalty in the shoot-out, and despite conversions from Alfie Doughty, Reeco Hackett-Fairchild, George Lapslie and Ahearne-Grant, the Addicks went out 5-4.
Charlton: Mitov; Barnes, Cummings, Bowry, Edwards; Dijksteel, Carter (Charles-Cook 66), Lapslie; Yamfam (Doughty 69), Ahearne-Grant (Maloney 90), Hanlan.
Subs (not-used): Beeney, Maloney, Doughty, Hackett-Fairchild.
Goals: Hanlan 105, Ahearne-Grant 105, Charles-Cook 109.
Booked: Bowry 69 (foul), Lapslie 89 (dissent), Ahearne-Grant 120 (time wasting).
Hull: Andrew; Lenihan (Clackstone 91), Tymon, Batty, Rodgers; McKenzie, Annan, Clark (Ter Horst 87), Luer (Edwards 78); Olley, Bowen
Subs Not Used: Croudson, Fleming.
Goals: Bowen 93, Ter Horst 102, Edwards 120.
Referee: Paul Kelly (Kent).