The Ginger Prince, known for his masterful long-range passing and hard-nosed tackling, will be extremely hard to supplant. Currently, two players are on the top of Manchester United's shortlist: Wesley Sneijder and Luka Modric.
While both are well qualified to garner a place in the United XI, Ferguson has recently stated that he has no interest in Wesley Sneijder, while others have say a deal is soon to be struck. Sneijder himself has been extremely coy about his future.
Modric, on the other hand, has openly expressed his desire to play at Stamford Bridge next season. Concurrently, Tottenham manger Harry Redknapp has been adamant that Modric is going nowhere.
Since a central midfielder is of necessity, here are five more players who could fit the mold.
Linked with United early last year, Schweinsteiger would be an ideal player for the Red Devils. Accustomed to the pressures of a top club, Schweinsteiger has already played for the Bayern first team for nine years, operating as their central midfield maestro.
His power and the accuracy of his long shot would give United a goal threat behind Rooney and Hernandez, possibly allowing the strikers more opportunities for themselves.
Schweinsteiger has also shown his defensive prowess and his ability to operate as more of a defensive midfielder, best evident in the 2010 World Cup vs. Argentina where he shut down Lionel Messi.
An established German international and still only 26, Schweinsteiger may still have his best years ahead of him.
Last year he signed a contract extension with Bayern, tying him down to the club until 2016. A combination of his quality and contract would garner a significant transfer sum.
A deep-lying midfielder, Xabi has all of the qualities to make a seamless transition into Manchester's midfield. A player with incredible vision and top-notch passing ability, Alonso could provide Rooney, Hernandez, Young, et al. with that clever ball that leads to a goal.
He knows the English game well, after spending five years at Liverpool, so transition time would be minimal. Furthermore, he knows the likes of Xavi and Iniesta well through the Spanish national team, and may know the secret to defeating the Barcelona midfield.
At 29, this wouldn't be a signing for the future, which goes against Sir Alex Ferguson's (and the Glazers') recent transfer activity. Additionally, Madrid has given no indication that he would be allowed to leave.
Probably best known in the U.S. for his elbow on Brian McBride in the 2006 World Cup, De Rossi is a fantastic talent in the defensive midfielder role. Capable of holding his own with the best of Serie A, De Rossi has been one of the few reasons why Roma have been marginally successful in recent years.
Possessor of a wicked long-range shot and fearsome defensive capabilities, this 27-year-old could be drawn to United with the prospect of significant silverware.
A self-proclaimed Roma fan, it could be difficult to draw De Rossi from the club of his youth, as well as the club his father played for.
De Rossi is also set to receive a new contract offer from Roma.
Heavily linked with United in 2010, Defour is a young Belgian talent that could develop into a central midfield magician.
After wonderful seasons in 2007-08 and 2008-09, when he helped Liege to successive titles and captured Belgium's Golden Shoe, Defour became heavily linked with both Untied and arch-rivals Liverpool.
Still only 23, Defour has a seemingly bright future ahead.
After suffering through injuries (including a broken foot) in recent seasons, there is a significant worry that Defour will be too injury-prone, especially in the rougher English game.
If rumors are true, Defour could be on his way to Russia, with the likes of Spartak Moscow mentioned.
Although a Belgium international, Defour is largely unproven on the largest stage. Easily the biggest gamble on the list.
Who said replacing Scholes meant going into the transfer market?
Sir Alex Ferguson has shown a significant amount of belief in the young Brazilian (still only 23). He's been with United since 2007, so he knows the ins and outs of the club by now.
Anderson received an increase in playing time during the 2010-11 campaign, and responding with his best season yet. Best exemplified by United's demolishing of Schalke in the Champions League semi-finals, Anderson's attacking ability would be an asset.
Though his defensive capabilities have come into question, they could be covered by a more defensive-minded partner, such as Fletcher or Carrick.
One big plus: he wouldn't cost a dime extra.
Though improving, Anderson's defensive ability has come into question.
His discipline has also been an issue in the past, with United fining him £80,000 in January 2010 for reportedly returning to Brazil without permission.