The World Cup is not only football's biggest tournament, but it also serves as a shop window for players to impress onlooking clubs.
Jose Mourinho's first season back at Chelsea ended in disappointment as the Blues failed to land a trophy, but fans can be confident that they will mount a title challenge next season having come so close this time around. Mourinho will now be planning a summer of spending in order to get Chelsea over the finish line, and some World Cup stars may be of interest.
With central midfielders and strikers needed at Stamford Bridge, you can be sure that Mourinho will be bringing some new faces in to fill those holes, whilst depth could also be added to the defence. With that in mind, here are five stars playing in Group H at this summer's World Cup that could fit the bill.
Jan Vertonghen, Belgium
With David Luiz set to sign for Ligue 1 giants Paris Saint-Germain and John Terry's career drawing to a close, Mourinho must look to add another centre back in the near future. He may have had a shaky second season at White Hart Lane, but Tottenham star Vertonghen still possesses superb ability, and his versatility to play left back could be appealing to the Blues, who have let Ashley Cole leave the club.
Axel Witsel, Belgium
Another problem area for the Blues is in midfield, where Nemanja Matic needs a long-term partner. Ramires and John Obi Mikel have both been linked with summer exits, whilst Frank Lampard has already left the club after his contract expired. An option could be Zenit St. Petersburg star Witsel, who Mourinho tried to sign during his reign as Real Madrid boss. The former Benfica man will be key to the Belgium midfield this summer, operating in front of the back four.
Alan Dzagoev, Russia
Despite already having a plethora of attacking midfield players, Chelsea continue to be linked with more as cover for the likes of Oscar, Willian and of course, Eden Hazard. Having been linked with a move after he impressed in Euro 2012, CSKA Moscow midfielder Dzagoev could put his name back on Chelsea's radar this summer with positive displays for Fabio Capello's men.
Aleksandr Kokorin, Russia
Even if Chelsea do sign Diego Costa from Atletico Madrid this summer, they still need more strikers with Samuel Eto'o gone and Demba Ba seemingly on his way out. An option to consider this summer would be Russia's Kokorin, who could be set to breakout at the World Cup. The 23-year-old has an impressive scoring record back in Russia, and Chelsea have been known to sign Russian League players under Roman Abramovich's ownership before, such as Jiri Jarosik, Yuri Zhirkov and Willian.
Heung-Min Son, South Korea
If Chelsea do decide to add another attacking midfield player who can play up front, then they may rekindle their interest in Bayer Leverkusen's Son. The 21-year-old was a target for the Blues last summer whilst with Hamburg, and having impressed again in the Bundesliga, the South Korean international is drawing plenty of interest. South Korea's hopes will depend largely on how well Son plays as their most creative and potent outlet.