Willian Borges da Silva has been at Chelsea for the best part of 6 seasons and has been good for the Blues. He has been a part of two Premier League title-winning teams and has been good whenever he has been called upon.
One of the few shining lights for the club during the last bad days of the Jose Mourinho era, the Brazilian winger has appeared 248 times for the Blues scoring 46 goals and making 42 assists.
However, the 30-year-old's powers have been on the wane in recent seasons. He has struggled in Maurizio Sarri's system where the emphasis is on playing the ball forward with quick passing and intelligent movement.
Willian's dithering on the ball and his poor decision making has made him a bad fit for Sarri's preferred style a.k.a Sarri-ball. With the January transfer window approaching, Chelsea might want to go into the market and get a better, more-fitting replacement.
Here is a look at 5 possible replacements for Willian Chelsea might look to sign in the winter transfer window:
#5 Gelson Martins (Atletico Madrid)
The latest product in a long line of exceptional Portuguese wingers, the 22-year-old Cape Verde-born winger has not had the best start to life in Madrid.
Diego Simeone is notorious for choosing to slowly integrate new players, hence Martins has not had the start many were expecting. A speedy and inventive wide player who is able to be effective on both flanks, he excels more on the right (Willian's current position).
Similar to Ricardo Quaresma, the former Sporting Lisbon player has the skill and speed to beat defenders and get into space. While he is not the strongest winger in terms of strength, his love for hogging the ball helps him retain possession more often than not.
He is very much a classic style winger, his ability to stay wide and stretch the game could be brilliant for Chelsea especially when playing against massed defences.
He has a lot to improve on in terms of decision making, goals and assists. In Martins, Sarri would be getting a player similar to what he had with Jose Callejon at Napoli. The Italian really worked on Callejon during their time together and helped the former Real Madrid winger to become a better player/goalscorer. The same could happen with the Portuguese international.
It is unclear how much Atleti might ask for the player given that he just joined (on a free transfer). However, he could be a superb long-term replacement for Willian.
#4 Mikel Oyarzabal (Real Sociedad)
One of the rising stars of Spanish football, Oyarzabal has been one of the best players in La Liga this season. He has been the go-to guy for a Sociedad side that is struggling.
The 21-year-old is the latest in a line of diminutive, left-footed Spanish midfielders whose major qualities include intelligence, creativity and a good instinct for getting into goalscoring positions (e.g David Silva).
Among the youngster's greatest strengths is his exceptional crossing ability, something which Sarri’s men should do more of especially in tight games. Unlike Willian, the Spaniard reads the game better and is quicker at releasing passes; a central tenet of Sarri-ball.
Oyarzabal is always reading the game, assessing the next phase of play and running into space to provide an outlet for teammates. This is something he has in common with Eden Hazard and Lorenzo Insigne; two players who have thrived in Sarri's system. This would be brilliant for the Blues as it means he could be used to stretch play on either flank or in case of an injury, he could fill in for Hazard in that central free role.
One of the captains at La Real following Xabi Prieto's retirement, Oyarzabal recently signed a contract extension and could cost the Blues as much as €80m.
#3 Nabil Fekir (Olympique Lyon)
The heart and soul of Les Gones, Fekir has not had a great start to the season. Following his limited participation in Les Bleus' World Cup-winning campaign, the failed transfer to Liverpool seems to have affected his game (coupled with injuries).
However, his display in Lyon's shock win over Manchester City in the Champions League has served as a reminder of his quality. Creative, clinical, intelligent and an absolute joy to watch, he was brilliant for Lyon last season.
In Bruno Genesio's side, Fekir is the creative fulcrum that always looks to play on the front foot with pacy, skillful forwards Bernard Cornet, Memphis Depay and others. In a Chelsea team with an emphasis on moving the ball quickly, Fekir could be brilliant. Able to drift to the wings or play centrally, he could form a great partnership with Hazard as his passing could be key to opening up opposing defences, unlike Willian who relies too much on pace and running instead of creativity.
How much he would cost isn't clear but Lyon reportedly accepted a £52.5m offer for the French international from Liverpool. He could cost less depending on the Blues' determination to get him in.
#2 Wilfried Zaha (Crystal Palace)
In terms of Premier League-ready wingers who can fit into the Chelsea team immediately; the golden boy of Selhurst Park is atop the list.
The 25-year-old Ivorian international has been sublime this season despite the injury problems he has had. He is integral to Crystal Palace’s survival hopes and it is not an exaggeration to say his presence gives the team that extra quality that no one else in the squad can deliver.
Pacy and elusive with brilliant dribbling skills and the ability to beat his man at will, he has made the left wing his own and is also adept at playing as a right winger or at times, function as a false 9 if need be.
Zaha’s verve and directness would be a change from the ponderous play of Willian. Able to play across the front line will, he could be to Chelsea what Dries Mertens is to Napoli in terms of versatility, assists, and goals. His ability to play off a striker means that he would gel well with either Alvaro Morata or Olivier Giroud.
He will definitely not come cheap as a £70m price has been mooted for the Eagles' most valuable asset (he just signed a contract extension).
#1 Leon Bailey (Bayer Leverkusen)
The one youngster who ticks all the boxes for what Willian's replacement should be, Bailey had a barnstormer last season.
A pacy and skillful dribbler who is capable of functioning on either flank, he has a mean left foot and is also excellent at dead ball situations Like most wingers, he is not the tallest player but what he lacks in height, he more than makes up for in agility and pace.
Capable of also being deployed as a false 9 as well, Bailey has been the standout performer of a young crop of excellent attacking talent at Bayer Leverkusen.
His brilliance would be of great benefit to the Blues as his pace, shooting ability and improved crossing would mean less creative work for someone like Hazard. Morata and Giroud would also benefit from his excellent service.
Bayer Leverkusen is reportedly said to be willing to do business for £100m, a rather steep price.