January is often a crazy period in the European football season, but while it is not always imperative to sign players in order to hit targets come May, it can be a wonderful opportunity to capitalise on positions that certain clubs find themselves in.
Clubs have the option of establishing themselves in positions that they did not envisage themselves being in at this point, so it is to the fans' dismay when clubs either refuse to gamble in the market or fail to push deals over the line.
As well as the following five sides, another team who may be a little disappointed by their business in January could be Liverpool—who look to fight off Everton, Spurs and Manchester United for that invaluable fourth spot.
Rodgers may regret not bringing in reinforcements, but if the squad stays healthy, they can achieve their target of fourth, which is why I do not think their lack of business in January will mean they will suffer over the coming months.
Of course, bad luck with injuries can change everything, but the majority of clubs cannot budget for this always.
Valencia is an intriguing team, who did multiple deals in the window, and while Los Che will have next to no chance of a place in the top four, they can still reach the Europa League spots.
Vinicius Araujo, Philippe Senderos, Seydou Keita, Ruben Vezo and Edu Vargas all arrived, so it is tough to say they have had a bad window.
All of those deals have doubts as to whether they will prove to be successes, at least in the short term.
So departures of Sergio Canales, Helder Postiga, Dorlan Pabon, Adil Rami, Ever Banega and Andres Guardado may yet prove costly.
Results have not been good enough, so you cannot blame the club for rolling the dice and making plenty of changes, but it remains to be seen whether so many will have a positive or negative effect.
Here are five other teams who could suffer after a poor January transfer window.
Manchester City have a formidable squad, but when examined closely, there are two positions that may be a little bare.
Centre-back and defensive midfield are those concerned and City pulled out of a late move to sign Porto's Eliaquim Mangala and Fernando for £50 million, according to the Telegraph.
Without Fernandinho, Chelsea bossed City's midfield and Yaya Toure was exposed, which could become a trend if the Brazilian is out for a prolonged period of time.
Martin Demichelis is a disaster in the midfield and a lack of a trusted deputy for Fernandinho may come back to haunt Manuel Pellegrini, with Jack Rodwell and Javi Garcia not trusted by the Chilean.
While Matija Nastasic is a superb talent, he is experiencing teething problems adapting to the Premier League, and with Demichelis being exposed persistently for being square on and woefully lacking in pace, Vincent Kompany does not have a trusted partner at the back.
City may well go on to win multiple trophies, but their destiny could hinge on the fitness of Fernandinho, rather than Sergio Aguero.
Arsenal are sitting pretty at the top of the league, but Arsene Wenger may regret not making a splash in the January transfer window.
A wonderful opportunity presents itself to the Gunners, and fans have persistently cried for a respectable back-up to Olivier Giroud.
The Frenchman has been burdened with the responsibility to play almost every game up top—without decent cover, Wenger is unable to give him a rest.
Fatigue could become an issue as the season moves towards a crescendo, but Wenger may have wanted to buy another type of player.
Theo Walcott has been ruled out for the rest of the season, and Arsenal appear to lack an option in behind without the England international.
Julian Draxler was strongly linked, but Arsenal eventually ended up with Kim Kallstrom, who will hardly set pulses racing at the Emirates.
Lazio could regret the January transfer window they experienced, as they sold their star midfielder Hernanes to rivals Inter Milan.
The Brazilian has been off form lately, but failure to bring in players to strengthen the squad may put the Biancocelesti's hopes of claiming a Europa League place beyond them.
Edy Reja has had a positive impact since returning to the club, but it is tough to see him bridging the four-point gap to Hellas Verona for that last Europa spot.
Especially with Milan and Inter set for better second halves of the season.
Balde Keita is a phenomenal talent, but it is unfair to expect him to inspire the team so soon into his career.
Lucas Biglia and Felipe Anderson can combine to reduce the impact of Hernanes' loss, but with both struggling for consistency since arriving in Rome, Lazio may have to settle for a mid-table finish.
Verona would not have expected to be in the mix for a Europa League spot, but Andrea Mandorlini's side have been the surprise package of Serie A this season.
Unfortunately for Hellas, they lost star midfielder Jorginho, who joined Napoli, and without a sufficient replacement, a slide down the table appears inevitable.
Perhaps the club will not be too bothered by missing out on a place in Europe, but it is certainly an achievable target given the struggles of Inter, Milan and Lazio, all of whom are in transition currently.
Juan Manuel Iturbe will have to continue to inspire the side, while Marquinho arrives on loan from Roma, which is a boost to some extent.
But it does feel as if they have missed the opportunity to capitalise on a sensational start and push on to clinch a place in Europe next season.
Benfica lost Nemanja Matic to Chelsea in January, so in losing their best player, the window can never be considered a success.
Squad players Ola John and Bruno Cortez also departed, and without any significant additions last month, they may have handed Porto a big advantage entering the second half of the season for the title race.
Porto managed to hold on to Eliaquim Mangala and Fernando, which becomes ever more important.
Jorge Jesus has been forced to call up players from the B team, including Joao Cancelo, Bernardo Silva and Helder Costa, who all came on as substitutes in the cup match against Gil Vicente.
The window was even more disappointing due to the failure to bring in some much-needed cover for injured forwards Oscar Cardozo—who has only just returned after almost three months out—and Eduardo Salvio.