For the last eight seasons, Rio Ferdinand has been a fixture on Manchester United. His defense, leadership skills, and experience has propelled Man U to four premier league titles.
Although Ferdinand has been such a key player, it appears like he and Manchester United will move on separately.
After being ejected for four games last season, missing the World Cup due to injury, and entering his mid-30s, Ferdinand's career may be over, at least with Manchester United.
If Rio Ferdinand leaves the team, here are 15 players that can replace him, both in the locker room and on the field.
Unlike most players being pursued by Sir Alex Ferguson and Manchester United this summer, Burdisso is relatively unknown.
Burdisso, who is only 22, played at Rosario Central of the Argentinean Premier League during the 2009 season. In 44 appearances, Burdisso scored three goals.
Besides Manchester United, Manchester City is bidding for his services. Regardless of what team gets him, Burdisso seems aligned for a big payday during the transfer window.
Three weeks ago, it looked like Joe Cole was headed to Manchester. The team needs an experienced midfielder and Cole's success at Chelsea made him a likely candidate.
Recently, Manchester United announced it didn't have interest in signing Cole. Although the team denied rumors of a move to Manchester for Cole, anything can happen.
Old Trafford is giving mixed signals about Cole.
I personally think Cole would be an ideal fit for Man U but won't sign with them. Instead, Cole may be headed to Arsenal or Tottenham Hotspur.
One of the most intriguing options for Manchester United this offseason is Rafael Van Der Vaart. Van Der Vaart is a dynamic midfielder that can effectively play both offense and defense.
For the last two seasons, Van Der Vaart has played for Real Madrid in La Liga. He has scored 11 goals in 58 appearances.
Signing Rafael Van Der Vaart seems like a no-brainer for Manchester United. The team desperately needs help in its midfield and Van Der Vaart can also play back on defense if needed. He is a multi-functional player that could mitigate the loss of Ferdinand.
On January 26 2010, Manchester United signed a pre-contract agreement with Chris Smalling.
Before playing on Fulham for the past two seasons, Smalling was a member of Manchester United for his rookie campaign.
If Sir Alex Ferguson isn't able to sign the transfers he is targeting, Smalling will have to step up and prove his worth.
He has the skill set to make an impact on defense, but his occasional lapses can hurt his chances of being an everyday player.
If Rio Ferdinand leaves Old Trafford, the team will lose an experienced veteran on defense. Lassana Diarra can fill that void.
In the past five years, Diarra has played for Arsenal, Chelsea, Portsmouth, and Real Madrid. This unmatched experience has made him very popular in the Manchester United organization.
His greatest flaw is his work ethic; he has gotten into arguments with many of his coaches.
It looks like Man U will have to fork over 20 million euros for his services next seasons. Manchester United is the favorite for Diarra but Arsenal is also reportedly interested.
According to the London Daily Mail, Manchester United will target Giorgio Chiellini. To entice Chiellini, the team is poised to offer him 25 million euros a season, much more than his current 1.7 million euro contract.
Throughout his career, Chiellini has played center back in Serie A and on the Italian National Team. Most recently, Chiellini has played for Juventus.
Chiellini is best known for his dominating presence in the air. He is one of the best players in football to defend headers and has plenty of experience playing next to star talent.
He shouldn't have a problem making an impact for Manchester United should the team sign him.
If Rio Ferdinand or Nemanja Vidic leave Manchester United during the transfer period, expect the team to sign Simon Kjaer.
Once the Danish talent of the year, Kjaer is an up-and-coming center back. He was an important player on Denmark's defense during the World Cup and has played for Palermo the past two seasons.
Growing up, Kjaer was a Liverpool fan but he is more than willing to join Manchester United this offseason. Inter Milan, Manchester City, and Tottenham are also competing for Kjaer, who is an 11 million euro rated player.
In an ideal world, Manchester United would love to retain Nemanja Vidic, especially if Ferdinand doesn't return.
During the last three seasons, Vidic has established himself as a premier center back.
Vidic has also been the star player on the Serbian National Team, leading it to the World Cup in 2010.
In the 2008-09 season, Vidic helped Manchester United to a record-breaking run of 14 scoreless sheets and was awarded the Barclay's Player of the Season.
It seems apparent that Vidic would prefer a move to Real Madrid. His wife isn't content in Manchester, and Vidic would be looking at a 25 million euro payday, should he move.
The best replacement for Ferdinand may be his own teammate.
How much would you be willing to overbid for a talented but unproven player?
This is the question currently facing Manchester United. Jorge Rolando, the center back for Porto, is looking for 28 million euros a season from Manchester United.
At only 24, Rolando is relatively inexperienced for a mega-contract. He is considered to play a similar game as Ferdinand and can be the face of Manchester United for years to come.
It is a tough decision for Old Trattford but it appears Rolando could be joining Man U next season. Sir Alex Ferguson is willing to overpay for role players and Rolando fits the bill.
One of the biggest names on the transfer market will undoubtedly be Maicon.
During the last four seasons, Maicon has been a fixture on Inter Milan. The Brazilian right-sided fullback has proved his excellence, both on offense and defense.
In his four years at Inter Milan, Maicon has scored 13 goals. Maicon has also scored seven goals for Brazil since 2003, including a brilliant shot against North Korea in Brazil's first game of the 2010 World Cup.
Very few players combine speed and accuracy as Maicon does. His talented play and knowledge of the game instantly makes his teammates play better, making him a perfect fit at Man U.
Real Madrid has reportedly offered Inter Milan 30 million euros for Maicon but if Manchester United significantly outbid Real Madrid, Maicon could be theirs.
According to the London Sunday Mirror, Manchester United is poised to offer Sneijder more than 20 million euros.
Besides Manchester United, Real Madrid is bidding for the Inter Milan and Netherlands National Team All-Star.
Prior to joining Inter Milan in 2009, Sneijder played for Real Madrid for a season. It looks like Jose Mourinho will give Sneijder one more chance to prove himself.
Sneijder is one of the most accurate passers in soccer. His play-making abilities are second to none and he always seems to be a part of scoring chances.
His passing prowess has led the Netherlands past the Group Stage in the 2010 World Cup, and Inter Milan to the 2010 Champions League title.
Raul Meireles is the perfect player for Sir Alex Ferguson's system. He is experienced, sophisticated, and durable.
Since 2004, Meireles has proven his worth for FC Porto. Although he isn't the flashiest midfielder, Meireles is a great long-range passer and is able to open up opportunities for his teammates.
In the 2010 World Cup, Meireles scored the first goal for Portugal in its 7-0 romp of North Korea. Throughout the entire tournament, Meireles has shown teams in the EPL his worth.
If Manchester United wants to sign Meireles, it only has to pay 12 million euros, considerably less than the biggest names on the market.
Although Glen Johnson hasn't been linked with Manchester United, he is an interesting option for the team.
Throughout his career, Johnson has played for Chelsea, Portsmouth, and Liverpool. He is also a member of the English National Team and was a starting defender for Fabio Capello throughout the entire 2010 World Cup.
Johnson is a very intimidating defender who rarely suffers from mental lapses. In addition, Johnson is surprisingly good on attacks.
As of now, Arsenal seems to be the front-runner for Johnson. Signing him would cost approximately 15 million euros, less than many other defenders with a similar skill set.
Much like Ferdinand, Johnson would be a fan-favorite for his attitude, determination, and leadership skills.
Call this a long-long-shot but if Sir Alex Ferguson wants to save some money and take a chance on a skilled but unpolished player, Jay DeMerit may be a target for Manchester United.
Yes, you heard me right. Jay DeMerit of the U.S. World Cup team may be a consideration for Manchester United. Not Clint Dempsey, not Landon Donovan, but Jay DeMerit.
In the 2010 World Cup, DeMerit grabbed the attention of scouts throughout the world when he brilliantly shut down Wayne Rooney in England's first game. DeMerit showed flashes of brilliance in this game, perhaps enough to get a shot in the EPL.
Currently, DeMerit plays for Watford in the English Championship League (one level below the premier league).
This is a very interesting move for Old Trafford, especially if it signs a few high-contract transfers.
In reality, the chances of this happening are close to none.