Captain. Leader. Legend. Those are the three words Real Madrid fans offer when they have to describe Sergio Ramos. After joining from Sevilla in the summer of 2005 for €27 million (most expensive Spanish defender at the time), Sergio Ramos has served Real Madrid for 15 years now and has had an illustrious career.The 34-year-old centre-back has not only been one of the best in the business for 15 years, but he's also chipped in generously with crucial goals; his set-piece ability is a particularly special talent for someone who plays in the backline.Sergio Ramos scored 11 La Liga goals this season to break the record for the most goals scored by a defender in a Spanish top-flight season this century.Sergio Ramos has scored 11 La Liga goals this season, the most by a defender in a single season in the 21st century. LEGEND 🙌 pic.twitter.com/0pMWPpWhQK— ESPN FC (@ESPNFC) July 19, 2020With that being said, Real Madrid will find it awfully difficult to find someone who can replicate what Sergio Ramos has done for the club. However, it is something that Los Blancos will have to direct their attention towards straight away.On that note, let's take a look at five players who could potentially replace Sergio Ramos at Real Madrid.5 replacements for Sergio Ramos at Real Madrid#5: MarquinhosReal Madrid v Paris Saint-Germain: Group A - UEFA Champions LeagueWhile some might argue that the Paris Saint-Germain centre-back Marquinhos has not hit the heights that were expected of him when he first joined PSG in 2013 for £31 million, at 26 years of age, he still has plenty of time to do that.While he might not be the tallest centre-back around, he still makes his presence known in aerial duels. Marquinhos has made 19 appearances for PSG this term in the Ligue 1 and has helped them keep 10 cleansheets.Le 1⃣9⃣ juillet 2013, notre guerrier @marquinhos_m5 nous rejoignait. Le début d’une longue histoire ✊Déjà 7️⃣ ans, 𝑴𝒂𝒓𝒒𝒖𝒊 ❤️💙#OnThisDay pic.twitter.com/mYgetmSE1W— Paris Saint-Germain (@PSG_inside) July 19, 2020The Brazilian is an impressive passer of the ball and is a great asset when a team is trying to play out from the back. He also possesses a good understanding of the game and is adept in cutting passing lane and regaining possession of the ball.Having won 20 titles with Paris Saint-Germain, six of them league titles, there is no doubts as to whether Marquinhos has a winner's mentality - something that Real Madrid will want to look for in a Sergio Ramos replacement.#4: Aymeric LaporteAymeric Laporte would be a great fit at Real Madrid.One of Pep Guardiola's most expensive acquisitions at Manchester City, Aymeric Laporte has been linked with Real Madrid for a while now.In fact, the player himself had been quizzed about the speculation a while back and though he chose to play it down, the possibility of a move cannot be entirely downplayed. He had told EL Chiringuito via The Times: “I am very happy here at Manchester City. I am enjoying my football here."We are doing great things here. In the last two years we have won eight trophies.”Laporte offers a level-headed option at centre-back. Besides, the Frenchman has prior experience of playing in the La Liga after having blossomed to the player he is after spending eight years at Athletic Bilbao.The 26-year-old is renowned for not rushing into tackles and possesses elite passing abilities. However, he was sidelined for a good chunk of the season and will cost Real Madrid a lot of money as well.#3: Milan SkriniarMilan Skriniar (left) in actionMilan Skriniar has been the subject of interest of several top clubs like Manchester United and even Barcelona who have been looking to strengthen their centre-back options. The 25-year-old Slovakian, after joining Inter Milan in 2017, has grown in stature and has become one of the most sought after young defenders in Europe.Skriniar won't come for cheap, though. He has been Antonio Conte's go-to man at Inter Milan during this season, and it's safe to say that the manager's trust has been paid off. Skriniar is a good passer of the ball and conducts his duties in a calm manner even when the going gets tough.The Slovakian is also not one to shy away from a challenge. However, if there is one drawback to his game, it is his aerial ability. Skriniar may not be able to dominate La Liga attackers in the air as well as Sergio Ramos does right now. And he will also cost Real Madrid around £70 million.