The dawning of the new year brings an end to some loan spells while some continue, and here, the official Chelsea website looks at how those players plying their trade elsewhere during the first half of the season have fared.
Having moved to West Bromwich Albion on a season-long loan at the beginning of the campaign, Romelu Lukaku continues to go from strength to strength under the guidance of Steve Clarke at the Hawthorns.
The Baggies have been one of the form teams in the first half of the season, and the Belgian striker has played a key role in taking them to seventh place. After scoring on his debut, a 3-0 opening-day win against Liverpool, he has gone on to score seven times, including the winner in their 2-1 win against Norwich City three days before Christmas.
Early in the season Lukaku had to be content with cameo substitute appearances, but such has been his impact, he has forced his way into the side, becoming a regular starter of late.
His compatriot, Kevin De Bruyne, has also enjoyed a decent end to 2012, while representing Werder Bremen in the Bundesliga.
The 21-year-old has netted four times since moving to Germany, with his most recent goal, an 82nd-minute strike, proving decisive in a 2-1 win against Fortuna Dusseldorf, and he has featured on a regular basis, ironically helping fill the void left by Marko Marin.
His versatility in attack has seen De Bruyne play in a number of different positions, including as a central striker in Bremen's away defeat at Borussia Dortmund.
Josh McEachran [pictured below] is another player who has flourished since gaining regular first team football, impressing in the heart of midfield for Middlesbrough as they bid to regain their top-flight status.
The 19-year-old, who has made 23 appearances, has been playing alongside Grant Leadbitter in Tony Mowbray's preferred 4-4-2 formation, a role which has seen the defensive side of his game improve, and thus far, it's a move which has proved mutually beneficial.
Nathaniel Chalobah joined Gianfranco Zola's Watford earlier in the season, and while the midfielder was originally scheduled to come back to Stamford Bridge this month, the move has yielded such success that he has now extended his stay at Vicarage Road until the end of the season.
Chalobah has, more often than not, been deployed as a lone defensive midfielder, and while the one blemish on his time at the club was a red card against Cardiff City, he has also got forward enough to find the back of the net twice, most recently against Burnley. He has made 18 appearances for the Hornets thus far.
Sam Hutchinson, meanwhile, whose time at Nottingham Forest got off to a fantastic start, has been out of action since September after sustaining a knee injury.
The defender had established himself in the side at right-back prior to his setback, and scored a crucial goal in the 2-1 win against Charlton at the City Ground.
However, he has recently returned to training and will be hopeful of enjoying an injury-free second half of the season.
Over in Spain, Michael Essien, currently on a season-long loan with Real Madrid, has been in and out of Jose Mourinho's side, making six league starts for the Spanish champions who currently trail table-toppers Barcelona by 16 points.
The Ghanaian played the full 90 minutes in Madrid's 3-2 defeat at Malaga shortly before Christmas, and scored his only goal in a 4-0 win over Real Zaragoza back in November.
Chelsea supporters are well aware of Essien's ability to play in different positions, and since moving to Madrid, as well as his usual midfield role, he has also played at both right-back and left-back, earning rave reviews for one performance in particular, the 2-0 win against Celta Vigo.
Elsewhere in La Liga, Thibaut Courtois [pictured below], currently enjoying a second season on loan at Atletico Madrid, continues to impress, playing in all but one of their league games so far this season.
At present, Atletico look to be the one team who could possibly keep pace with Barcelona domestically, but while their attack, as we found out to our cost, are capable of scoring goals at any time, defensively they have been equally sound, with Courtois playing an instrumental role, keeping eight clean sheets.
Since moving back home, Thorgan Hazard has enjoyed a good start to his spell with SV Zulte Waregem in the Belgian top flight.
Eden's younger brother has been primarily deployed on the left of midfield, although he likes to drift slightly deeper and dictate the flow of the game with his excellent range of passing.
So far, he has scored two goals for Waregem, but having also made his Belgium Under-21s debut earlier in the season, he will certainly be pleased with his progress to date.
Patrick Bamford [pictured below] made an instant impact after moving to MK Dons, earning the plaudits of manager Karl Robinson following his debut performance in a 5-1 win against Colchester United.
However, after suffering with a hamstring problem, his involvement was limited, and he went on to make only one more appearance for the club, the Boxing Day defeat at Walsall, where a reckless challenge forced Bamford out of the action with 10 minutes remaining.
Bamford is scheduled to return to Chelsea next week.
Young right-back Todd Kane has been gaining invaluable experience on loan at Preston North End in League One. Our Under-21s captain moved to Deepdale in November and has made three league starts, as well as featuring in their 2-0 FA Cup second round win over Gillingham. Kane is also scheduled to return to Chelsea early next week.
Goalkeeper Sam Walker made 11 league appearances over the course of the first half of the season for Bristol Rovers, although he was unable to prevent them from slipping into the relegation zone prior to his return to Chelsea, while Conor Clifford made only one appearance as a substitute during his time at Crawley Town.
Left-back Ben Gordon has returned to the club following a loan spell at Birmingham City, where he made only one appearance, the opening-day defeat to Watford.
Meanwhile, Archange Nkumu's loan spell at Colchester United was cut short after the 19-year-old suffered a bad run of injuries. He returned to Stamford Bridge a month earlier than planned.
Tomas Kalas continues to grow in stature while on loan at Vitesse Arnhem in the Eredivisie, playing in every league game this season so far.
The Czech defender, enjoying a second season with the Dutch side, also netted his first goal for the club in a 3-0 win against FC Groningen. Patrick van Aanholt, also in his second season at the club, has been a regular in the side as well, playing in all but one league game.
Gael Kakuta, meanwhile, our third player on loan at Vitesse, has steadily improved with every appearance, after injury delayed his involvement at the start of the season.
The 21-year-old has been used as a winger - on both flanks - and a central-midfielder, and has become an important member of a squad currently in fifth position.
Kenneth Omeruo is also enjoying his time in Holland. The Nigerian defender is currently on loan at ADO Den Haag for a second successive season, and has been a regular at the heart of the defence, featuring in all but one league game.
Jeffrey Bruma has struggled to find any sort of momentum while on loan at Hamburg, largely due to misfortune with injuries. The defender made his first league start since September in last month's 1-1 draw with Wolfsburg, although he has been featuring regularly as a substitute.
Currently on loan at his former club,Larje-Angereds I.F, Anjur Osmanovic, a creative midfielder, will be hoping for a fruitful second half of the season which will stand him in good stead before he heads back to Stamford Bridge.
Amin Affane, who was part of the team which won last season's FA Youth Cup, will be pleased with his involvement since joining Roda JC in Holland at the start of the season.
The Swedish winger, who scored his only goal for the club back in September, has made eight league starts for Roda, while also being used as an impact substitute on a regular basis.
Both Milan Lalkovic and goalkeeper Matej Delac are currently gaining experience in Portugal at Vitoria Guimaraes, but with starts being limited for both players, they will undoubtedly be eager to force their way into the side in the second half of the season.
Ulises Davilla is reaping the benefits of playing regular first team football after a disappointing spell with Vitesse last season. The Mexican attacker is on loan at Sabadell in Spain, and has been enjoying a solid run in the side. So far, he has made 15 appearances and scored five goals.