The January transfer window has been unusually quiet this year, with teams seemingly reluctant to put their hands in their pockets in an era of relative financial caution.
Very few big deals have actually gone through, but the rumour mill keeps churning, reporting on interest from the biggest clubs in the land about which players could be on the move and which managers are desperate to give their side that little edge.
And a little edge might be all they need at the very top of the table.
Just two points separate Arsenal, Manchester City and Chelsea at the summit of the Premier League and since all of those teams still have to play each other in the final few months of the season Arsene Wenger, Manuel Pellegrini and Jose Mourinho are assessing their squads and pondering if they have enough to take them down the stretch.
So which transfers could be decisive in shaping this title race? Which ones could determine the destination of the Premier League trophy?
Bleacher Report picks five deals that could define this season's Premier League.
Arsenal have the equal-best defensive record in the Premier League this season, having conceded just 19 goals in their 22 games thus far, with only Everton owning a comparable record.
However, as I wrote this week, much of that depends on the fitness of Laurent Koscielny and Per Mertesacker, who have formed an imposing partnership at the heart of Arsenal's defence this season.
Indeed, Arsenal have not lost a game that the pair have started and finished in over two years. Yet, should one or both of those defenders become unavailable, something not out of the question for a team with Arsenal's historical problems with injuries, then they are relying on Thomas Vermaelen, a man who has been in poor form for some time now.
Therefore, the addition of another centre-back could be prudent, especially if reports, per Corriere dello Sport (h/t to the Daily Mirror), that Vermaelen could be tempted away to somewhere like Napoli prove correct. Cheikhou Kouyate, a powerful young defender currently playing for Anderlecht, has been mentioned as a possible target, and he would make a certain amount of sense.
Kouyate himself seems keen as well. His agent recently told Goal.com's Ed Aarons: "I think he would prefer to play in England because it will suit his style very well.”
Kouyate would not be a first-choice defender, but he could provide the insurance at the back that Arsenal need to sustain their title challenge.
So barren has the January transfer window been thus far that this is as yet the only deal on this list that has actually happened.
You might not think that signing a defensive midfielder would have a great impact on the title race. Matic is not a mere water-carrier but neither is he a player who will score or create the goals that could prove decisive for Chelsea in the league.
However, he does strengthen one of the few areas of real weakness in Mourinho's side, providing a stable and reliable option at the base of Chelsea's midfield, allowing the likes of Frank Lampard and Ramires to attack. When before they will have had half a mind on ensuring things are shored up in the middle, they could now focus on supporting the superb cast of attacking talent in front of them.
It also might ensure that John Obi Mikel's playing time at Stamford Bridge will be limited, something that may well come as a relief to all Chelsea fans of a slightly nervous disposition.
Re-signing a player who was packed-off as a makeweight in the David Luiz deal three years ago for £21 million might not look like the best business, or example of joined-up thinking but it fills a hole in Mourinho's side and could thus prove crucial.
It's relatively rare that Arsene Wenger admits he needs to dip into the transfer market, but, with several injuries to Arsenal's forward line, as well as their only specialist centre-forward Olivier Giroud not exactly being in sparkling form (he has two goals in his last ten games, per WhoScored), Wenger acknowledges that he may need to spend on a striker this month.
The Independent quoted him as saying this week:
Ideally if it's possible we'd like another striker. I'll give you my phone number, if you find an exceptional (player), you can call me over the weekend. Ideally, though we have not found anyone.
We are open to strengthening our squad if it's possible. But as well we have Bendtner back in the squad on Monday. Sanogo is back in the squad on Monday week.
But for us, it's important to know everybody can score. Ramsey is a goalscorer and he's not playing at the moment. Arteta can get us a goal and he's not playing. That's very positive, I think.
Several strikers have been mentioned as possible targets, from Porto's Jackson Martinez, per Metro, and Bayern's Mario Mandzukic to Real Madrid's Alvaro Morata, per Ben Burrows of the Daily Mirror, with Schalke's Julian Draxler thought to be a long-term target.
However, recent events might mean that the most realistic target is Juventus forward Mirko Vucinic. It looked like the Montenegrin forward was heading to Internazionale in a swap deal with Fredy Guarin, to the extent that he had a medical in Milan and Guarin was pictured at the Juve offices, but Inter eventually pulled out of the deal.
Therefore, Vucinic is available again, and he could provide the cover and flexibility that Wenger requires. Juve may prefer a permanent transfer to a loan deal, but Vucinic might be the most sensible, realistic and short-term option currently available to Arsenal.
In all honesty, this deal probably will not happen. Casillas himself has said that he not only wants to stay at Real Madrid for the rest of this season, but for next year as well.
He was recently quoted by AS (with translation by InsideSpanishFootball.com) as saying:
“I’m tired of talking about my situation. ... Yes, I see myself playing with Real Madrid next year. I need to enjoy myself, because as the manager said, we are in three competitions.”
In addition, Casillas has recently had a baby, and he appears to be content with his current role as Real's cup keeper, taking Diego Lopez's place for Champions League and Copa del Rey games.
However, with the World Cup in the summer, can Casillas really afford to stay? Can Vicente del Bosque afford to face Spain's toughest test in Brazil with a goalkeeper who has played minimal football this season?
Joe Hart may have re-established himself between the sticks for Manchester City but there are still signs of the old uncertainty that saw him dropped in favour of Costel Pantilimon earlier in the campaign, signs that must have made Manuel Pellegrini wonder if signing another goalkeeper would be a good option.
A loan until the end of the season for Casillas might make sense. It's understandable that he wants to stay at the club he's been with all of his life, but his pragmatic side could tell him a move is the most sensible option.
Of course, Manchester United appear to be out of the title race, for this season at least. They are 14 points behind leaders Arsenal, and their most realistic prospect for a successful campaign is to qualify for the Champions League and maybe win a cup.
However, Mata's move from Chelsea to Old Trafford could have an impact on the title race in other ways. It was perhaps no coincidence that talk of a transfer, per The Guardian's Jamie Jackson and Dominic Fifield, really began to seriously emerge a couple of days after Chelsea beat United at Stamford Bridge, which was the second and final time the sides will face each other this season, assuming they are not drawn together in the Champions League.
Mata in a United shirt therefore cannot harm Chelsea directly, because he won't face them in the Premier League and won't play at all in Europe, having already appeared for Jose Mourinho's side.
United still have to face Arsenal and Manchester City and if they can manage to take points from those games it will clearly help them, but he will arguably be of more value to Chelsea, given how tight the top of the table currently is.
The question of where Mata will fit in at United is one that has been debated to death already but it is undeniable that he will improve David Moyes' side, who have lacked inspiration and creativity, relying far too heavily on the 18-year-old Adnan Januzaj.
Mata won't help United to win the title, but he might help Chelsea do so, even if he isn't playing for them.