As the current campaign draws to a close, and with players returning to the club from loan, the official Chelsea website assesses how our players have progressed during their time away from Stamford Bridge...
In the Barclays Premier League, Romelu Lukaku has flourished during his loan spell at West Bromwich Albion, scoring 14 goals for the Baggies in 34 appearances which make him that club's top scorer. The Belgian began the season featuring predominantly from the bench, but after making a significant contribution Steve Clarke placed his faith in the striker by handing him regular starts.
Most recently, Lukaku turned in an impressive display and scored in their 3-0 win at Southampton. He was nominated for the PFA Young Player of the Year award and named West Brom's Young Player of the Season.
Michael Essien's season-long loan at Real Madrid has seen the Ghanaian feature on a regular basis, both in central midfield and at right-back. Jose Mourinho has shown his faith in a player who served him well during his time at Stamford Bridge by handing him starts in big matches, against the likes of Manchester City and Barcelona, and last night in defence versus Borussia Dortmund. Essien has made 17 Spanish League appearances.
Kevin De Bruyne's loan spell at Werder Bremen in the Bundesliga has been a success, with the Belgian attacker operating predominantly wide on the left of midfield, but also, on occasions, in a more central role. Up until last weekend, when a thigh injury ruled him out of the game against Bayer Leverkusen, De Bruyne had featured in every competitive game for the club this season, missing only four minutes from a possible 2820. He has scored six goals and contributed 10 assists thus far.
Lucas Piazon made an instant impact on his full Malaga debut after joining the Spanish side on loan back in January, setting up the winning goal for Javier Saviola in a game against Athletic Bilbao. More recently, the Brazilian has featured largely from the substitutes' bench as Malaga have struggled for form in La Liga, losing successive games against Real Sociedad, Osasuna and Valencia. Piazon was an unused substitute in the second leg of the Champions League quarter-final against Borussia Dortmund.
Thibaut Courtois continues to impress for Atletico Madrid in Spain. Having chased leaders Barcelona for much of the domestic campaign, Atletico have tailed off of late, slipping down into third behind city rivals Real. They were beaten 2-1 by Jose Mourinho's side at the weekend, but the season as a whole will undoubtedly go down as a success, both for the club and Courtois himself, who has produced a number of fine displays, keeping 18 clean sheets in the process.
For Nathaniel Chalobah, it's been a season full of positivity under the guidance of Gianfranco Zola at Watford. The youngster, playing in a defensive midfield role, has blossomed at Vicarage Road while playing regular first team football in a team pushing for promotion. Chalobah's performances have earned him England Under-21 recognition, while he has also added goals to his game, scoring five over the course of the season, including a stunning strike in the recent 2-1 win at Leicester City.
Elsewhere in the Championship, Josh McEachran has also enjoyed a solid campaign while on loan at Middlesbrough. The 20-year-old played regularly for the Teessiders, adapting his natural game to play in a 4-4-2 formation, while at times playing wide on the left.
The midfielder has missed the last few matches through injury. The Chelsea medical department have not had a chance to review his condition as yet due to his involvement with Middlesbrough, although they will assess him on his return to Cobham in the next few days and determine a treatment plan at that point.
At this point, the club have no indication that the player requires surgery.
After heading back to Blackburn Rovers for a second loan spell, Todd Kane has been heavily involved for the Ewood Park outfit, who preserved their Championship status with a 1-1 home draw against Crystal Palace last weekend. The right-back has flourished under the management of Gary Bowyer and has started the last nine league matches in succession.
Sam Hutchinson's loan spell at Nottingham Forest started well, with the right-back forcing his way into the side and scoring in a 2-1 win over Charlton Athletic. Unfortunately, he suffered a setback after establishing himself in the team and returned to Cobham for treatment.
Hutchinson went back to the City Ground in February, with Forest by that stage under the stewardship of Billy Davies, but he picked up an injury in a recent game against Barnsley, ruling him out of last weekend's win at Millwall.
George Saville has featured mainly as a substitute since moving to Millwall in January. He was, however, given 80 minutes in the Lions' recent 1-0 home defeat to Nottingham Forest.
Both Billy Clifford and Sam Walker benefited significantly from loan spells with Colchester United.
Clifford, embarking on his first spell away from Stamford Bridge, impressed almost immediately for the Essex-based club, turning in a number of accomplished displays in midfield. He scored his only goal with a stunning strike in a 2-0 win over Yeovil and played a pivotal role in helping Colchester avoid relegation.
Clifford has now returned to Chelsea and scored the only goal of the game in Monday's Under-21 win over Blackburn Rovers.
His Chelsea team-mate Walker kept nine clean sheets over the course of his spell, and both players will feel they made a huge contribution in maintaining the club's League One status, a feat which looked unlikely prior to their arrival.
Patrick Bamford, meanwhile, enjoyed an impressive second loan spell with MK Dons, scoring four goals in eight appearances for the club, including one on the final day of the season against Stevenage.
Bamford has also returned to the club and featured for our Under-21s against Blackburn.
Zulte Waregem , where Thorgan Hazard has been playing, trail league leaders Anderlecht by only four points in the Belgian top flight. On a personal note it's been a productive loan spell for Eden's younger brother. Since making the move, Hazard has made 23 league appearances for the club and scored three goals.
The Chelsea trio of Tomas Kalas, Patrick van Aanholt and Gael Kakuta, on loan at Vitesse Arnhem, have all enjoyed solid campaigns playing regular first team football. Kalas and Van Aanholt, in particular, have been near ever-presents for a side who are currently fourth in the Dutch top flight.
For Kakuta, 20 league starts indicate a promising campaign, although the French youngster has only found the target on one occasion. All three, however, played in the recent 3-1 win over Willem II, a result which helped strengthen their quest for Champions League football next season.
Brazilian right-back Wallace is currently playing for Fluminese having been loaned back to his former side ahead of joining the Blues in July. The 18-year-old was handed a start in their recent derby defeat to Flamengo.
After two years on loan at Hamburg, Jeffrey Bruma's time at the club has come to an end with the Dutch defender starting 10 league games during the current campaign.
On the international stage, it's been a season to remember for Kenneth Omeruo, who played an integral role as Nigeria clinched the Africa Cup of Nations crown in January. At club level it has been a slightly different story, with ADO Den Haag sitting in mid-table in the Eredivisie. The 19-year-old however has established himself as a regular in the side, starting 21 league matches, and will no doubt have benefited hugely from playing first team football.
Ulises Davila has enjoyed a more productive season at Sabadell than he did in the previous one with Vitesse Arnhem. The Mexican has played regularly over the course of the campaign, although he is currently out with a leg injury.
After spending the first part of the season on loan at Vitoria in Portugal, Matej Delac is currently on loan at his former club, Inter Zapresic in Croatia. The team have been struggling at the foot of the table for much of the season, although they recorded a vital win away at Zadar last week with the Chelsea goalkeeper completing the game.