The last four or five months of any season are obviously important in their own right. But with the World Cup looming large in the near future, the period between January and May takes on an added dimension for those players hopeful of making the cut for their national teams.
Playing at the right club for the back-end of 2013/14, then, is imperative. Whether one's current employers are not giving them enough time on the pitch or a lack of exposure to the international coach, a smart move before the January transfer window slams shut could make all the difference.
The following 10 players are on the verge of making Brazil 2014, but for one reason or another their current club situation could put that in jeopardy. But could the right transfer turn them into World Cup certainties?
Since moving to Zenit St. Petersburg in 2012, Brazil international Hulk has suffered from a phenomenon familiar to many South Americans lured to play in Russia and Ukraine. While showing consistently impressive form, the striker has seen his exposure drop and needs to fight for a place in the World Cup.
A less-than-overwhelming scoring record for the Selecao (eight in 32 caps) has contributed to Hulk falling down the pecking order. And with the likes of Neymar, Jo, Robinho, Bernard and Alexandre Pato all competing for places up front, a place in the squad is by no means assured.
A move to a higher-profile league in Europe could give Hulk the boost needed to assure his place in the hosts' plans.
By sheer reputation and renown, Diego Forlan is almost certain to win a place in the Uruguay squad. However, his contribution to Celeste efforts to win a second World Cup on Brazilian soil could well depend on how the next six months pan out for the No. 10.
After a fruitless year with Internacional in Brazil, Forlan has signed with Japanese side Cerezo Osaka for the next 18 months (via The National). It is debatable, however, if the J League will give one of the stars of the 2010 World Cup the shop window he needs to win a place in the first team.
A short-term loan move could still be made before January 31, and there should be no doubt that the veteran still has the quality to play at the highest of levels.
Julio Cesar's situation is a curious case. The undisputed No. 1 for his country and, at his best, one of the top goalkeepers in world football has been frozen out of contention in England's Championship. The odd chain of events surely cannot hold for long.
Cesar is still highly regarded by coach Felipe Scolari, but a season without playing for Queens Park Rangers is hardly ideal in the run-up to a home World Cup. A transfer, even if on a temporary basis, would be a vital step for the keeper to regain confidence and match fitness.
Juventus striker Fabio Quagliarella was criminally underused by Italy in the last World Cup. Given just 45 minutes by Marcelo Lippi, the forward nevertheless managed to score against Slovakia and come out of the disastrous group-stage elimination with some credit.
But unless Quagliarella can get regular action with the Old Lady, he could well find himself once more out in the cold.
The signings of Fernando Llorente and Carlos Tevez have pushed the striker out of Antonio Conte's plans, as he was mainly used as a substitute. If he wants to make a big impression at Brazil 2014, it may be time to leave Juve after four years in Turin.
As with many of the players on this list, it seems unlikely that Ashley Cole would miss out entirely on the World Cup. The fact is though that the Chelsea left-back is now not a regular at Stamford Bridge, and a loss of his England place could be the logical next step.
Leighton Baines is gaining on the veteran of the last three World Cups, who has been eclipsed by Cesar Azpilicueta in the Blues defence. A transfer away from Chelsea could be the answer to pick up speed in the last months before the World Cup begins.
While many South American youngsters struggle to make the jump to Europe, Erik Lamela took to life in the Roma starting line-up like a duck to water. Making the adjustment to Premier League football, however, has been rather more tricky for the ex-River Plate wonderkid.
Lamela pushed his way into Alejandro Sabella's Argentina plans through his form in the Eternal City. Now, with competition fierce for places in the squad, a lack of continuity and confidence in London could see him miss out on a first World Cup unless a change of scenery is forthcoming.
For many seasoned commentators, a young, exciting Belgium will be the team to watch in Brazil. But one of the more senior figures, Thomas Vermaelen, could be heading to football's most important competition with some unwelcomed doubts.
Despite his status as Arsenal's club captain, the centre-back has played just seven Premier League matches in the entire 2013/14 season. This lack of playing time can only hurt his chances of arriving in Brazil in top form.
Former Barcelona midfielder Thiago Alcantara must have been aware when moving to Bayern Munich that his new club would have him on the bench for long stretches of time. Without regular play, however, the 22-year-old talent has no chance of pushing his way into Spain's plans.
The man brought in by Pep Guardiola has participated in just seven Bundesliga matches, 12 overall, and there is no sign that will be changing before June. A short-term move could be the perfect tonic to establish the youngster as back-up for the likes of Xavi, Iniesta and Xabi Alonso for Brazil 2014.
Rosario-born Angel Di Maria is a key component of Alejandro Sabella's strongest Argentina team. But at Real Madrid, the signing of Gareth Bale has limited the versatile winger's playing time and led to rumours that he could pursue his career elsewhere.
There would be no shortage of interest in Di Maria should he decide to move from the Bernabeu. Manchester City, according to the Manchester Evening News, could be one of many options for the star if he wishes to reach the World Cup in the best condition possible.
While Di Maria has been linked to a possible Etihad Stadium switch, another established international could be on the way out. Joleon Lescott has seen his opportunities at Manchester City greatly reduced.
The centre-back needs a strong end of season to stand out in a position in which England have several options, but has seen little first-team action in 2013/14. A move to a Premier League rival could give the strong defender the time he needs to establish himself as a contender for Roy Hodgson's plans.