With the opening of the January transfer window, Arsenal has approximately 31 days to reinforce the Gunners as they move into the second half of the season.

Arsenal has had a decent first half of the season, they are currently in the semifinals of the Carling Cup, facing Barcelona in the round of 16 in the Champion's League, contending for the FA Cup and standing in third place in the Premier League behind the Manchesters.

The following list ranks the players most likely to move to Arsenal this January.

10. Gary Cahill

Does Bolton's Gary Cahill look good in Blue? Regardless of the degree to which the color matches this Englishman's pasty features, he is expected to be sporting it much more frequently when he transfers to Chelsea.

Cahill has been linked to Arsenal in the past. Typically, rumors of a transfer to Arsenal are coupled with a rumor about his price tag being $20 million plus. It therefore goes without saying that the stingy manager of Arsenal wouldn't be interested.

Cahill has been a world class defender at Bolton for a number of years. He certainly has the potential to thrive at a bigger club.

Considering Alex's injury, Ricard Carvalho's sale this previous summer and their fourth place standing, Chelsea is in the market for central defensive reinforcements this January. Cahill fits their bill, not Arsenal's.

I bet Cahill would thrive at Arsenal, since he is significantly better than Laurent Koscielny, Sebastian Squillaci and Johan Djourou...although Djourou is close and still improving.

9. Theofanis Gekas

Reports have linked both Nicklas Bendtner and Carlos Vela with moves away from the club. While it is highly unlikely that Wenger would sell both of them in January, such a move would leave the Gunners light up top.

As a result, the rumor mill has linked a number of strikers to Arsenal lately. Theofanis Gekas looks like one of the more probable transfers from a pricing standpoint.

This former Greek international has divided his professional career between Greece and Germany, currently playing for Eintracht Frankfurt, where he has scored 14 goals in 17 appearances for the club.

Gekas has now retired from international duty, so he won't have to worry about picking up injuries over breaks. Also, he is not cup-tied.

However, Gekas is 30, which makes him a unlikely Wenger signing. Although, he could be expected to move to a Champion's League team from an estimated $3-5 million.

8. Luis Suarez

Luis Suarez has been consistently linked to Arsenal over the past couple of years. Yet his valuation is known to be well north of 20 million, which has always been a great deal higher than manger Arsene Wenger's price range.

Suarez is 23, and thus could still have a reserve of unrealized potential residing between his Uruguayan ears. 

81 goals for 108 games for Ajax is an incredible return, although he probably wouldn't have been able to equal that total in a more prestigious league.

Suarez is an incredible talent in an area where Arsenal could be better—the main striker for the 75 percent of the season that Robin Van Persie is injured.

Regardless of Suarez's talent, his price tag will always make this rumor nothing more than just that.

7. Brede Hangeland

Brede Hangeland has been linked to Arsenal multiple instances in the past couple of years. The 29-year-old Norwegian is a world class central defender that plays on what is a mid-table Premier League team in Fulham.

Wenger has long admired Hangeland, but like most other potential transfers on this list, the price has been the sticking point. 

At 6'4'', Hangeland would be a tremendous addition to the Arsenal squad. He has the talent to match with Thomas Vermaelen in the Gunner's lineup.

Hangeland is getting on in years, and has a contract with Fulham through the 2013 season. As a result, a move away from Fulham continues to be unlikely.

6. Phil Jagielka

Phil Jagielka has been linked to Arsenal more frequently in recent years than just about any other player. Arsenal reportedly had an offer turned down by Everton last summer.

At 28-years-old, Jagielka is in the prime of his career. He has been a mainstay of Everton's lineup, when he can stay out of injury trouble.

Jagielka's persistent injury problems have led to some accusations of the English defender being injury prone. Since Everton is said to demand approximately $20 million for Jagielka, Arsenal is not likely to make another offer for this player in January.

5. Edin Hazard

Will Eden Hazard soon be sprinting ahead of Liverpool defenders on a regular basis?

The entire world is quickly coming to the realization that Eden Hazard is one of the more likely candidates for being soccer's next big thing.

Hazard is 19-years-old. The guy has been playing regularly since he was 16 and has played 88 times for Lille in Ligue 1.

Hazard is a two-time winner and reigning Ligue 1 UNFP Young Player of the Year award (I have no idea what UNFP stands for), and was very impressive against Liverpool in the UEFA Europa League, scoring the only goal in their 1-0 victory.

Hazard's links to Arsenal has only amounted to muted rumors, but he would be a great addition.

Considering his talent, and thus his price tag, I would expect him to be much more likely to go to Chelsea or Manchester United; or even more likely still to go to Barcelona or Real Madrid and sit on their bench.

4. Stefan Savic

Stefan Savic is a Montenegran defender that recently underwent a 10-day trial at Arsenal. The player currently plays at BSK Borca.

Savic is 19-years-old, and thus is a typical signing of Wenger's—raw talent that he can use to mold into the player of his liking.

However, Savic's club has reportedly demanded 2.5 million euros for their promising starlet. As a result, negotiations are currently at an impasse.

3. Jan Vertonghen

Jan Vertonghen was Thomas Vermaelen's partner at Ajax. Like Vermaelen, Vertonghen is also Belgian, relatively young at 22-years of age, and has a proven track record of scoring goals.

Vertonghen stayed behind at Ajax when Vermaelen moved on to Arsenal. The pair's familiarity with one another would make them likely to form a solid partnership at Arsenal. 

The fundamental question about this transfer: Would Ajax be willing to sell their star 6'2'' central defender? One would expect Vertonghen to command a high price, especially in the January transfer window, but no offers have been announced, so there is no way to know.

2. Per Mertesacker

What a difference a couple of months makes. Arsenal reportedly was interested in Per Mertesacker over the summer, but the German defender was not interested in moving from his current club, Werder Bremen.

Fast forward a couple of months, and now Mertesacker is now agitating for a move away from Bremen. The primary reason for his change of heart is the club's poor performance in the first half of the season. Werder Bremen currently sits in 14th place in the German Bundesliga.

Mertesacker has publicly stated that he would like to move, and that the Premier League is his desired destination.

Per Mertesacker could certainly plug the gap in Arsenal's team that keeps Laurent Koscielny and/or Sebastian Squallici regularly on the field.

Mertesacker has a significantly amount of experience for both club and country. At 26 years old, he still has a number of years of good soccer ahead of him.

Most importantly, Mertesacker is a giant. He stands at 6' 6'', which would add some much needed height to Arsenal's team.

1. No One

I realize that this is an anticlimactic ranking (and I hate being anticlimactic), but the point needs to be made—Arsene's most likely move this transfer window is to make no transfer moves at all.

It's astounding that one of the most respected managers in the league remains so inactive in the transfer market. Arsenal hasn't won a trophy in five years. Their competitors spend cash like its monopoly money.

Arsenal needs to spend money this transfer window if they want silverware. Regardless of this fact, Arsene's most likely move is to not make one.

Conclusion

Asenal faces Barcelona the month after the January transfer window closes. In the best case scenario, Thoams Vermaelen will pair with Johan Djourou, Sebastian Squillaci or Laurant Koscielny.

Center halves are Arsene Wenger's, and thus Arsenal's, achilles heel. Vermaelen is a world class center half, but they can't find  a partner with a quarter of his half.

Both Squillaci and Koscielny look like Phillipe Senderos 2.0—that is intended to be the opposite of a complement.

Arsenal needs a center half, any of them on this list would give them a decent shot against Barcelona's front three of Pedro, Villa and Messio in February.