Barcelona’s exit from the UEFA Champions League reinforced the need to buy a centre-back during the summer transfer window.
It’s highly unlikely that Barça will sign Mats Hummels because the German will remain loyal to Borussia Dortmund, who took him in as a Bayern Munich reject.
Thiago Silva could be signed if Barça are foolish enough to disregard financial stability i.e. submit a €40 million bid for the world-class Brazilian.
Javi Martínez has been solid at the back but by his own admission, but he’s not worth €40 million.
Here are 10 realistic centre-back options for Barça.
Sebastian Langkamp has been superb in the games I've watched.
His rise to prominence is quite similar to Philipp Wollscheid's breakout 2010-11 season for Nuremberg.
Langkamp's anticipation is second to none as evident with 89 interceptions in 24 games.
His tackling is generally clean which is why he has only accumulated four yellow cards.
What has impressed me is that he has stood tall in big games.
In a 2-1 loss to Bayern Munich last November, he made two crucial last ditched tackles, ended up with six tackles and eight interceptions—he must have drunk red bull during the half-time break.
When Augsburg surprisingly held Borussia Dortmund goalless, Langkamp cleared Robert Lewandowski's goal-bound effort off the line.
Talking about Dortmund, like Mats Hummels, Langkamp spent his youth with Bayern Munich.
It remains to be seen if Langkamp's form is a blip or a trend.
Álvaro Domínguez's positional awareness enables him to get away with not making many tackles.
Though the fact he has committed five more fouls than completed tackles is worrying.
David Cartlidge at Spanish Football.info said:
"Big leader in dressing room. Was told he gives the talks before games, and motivates the team. Not bad for a young pup. Recent call-up to Spain squad, and a new contract until 2015 testament to his development this season. Future captain IMO."
Mehdi Benatia is composed in possession and sophisticated enough to fit in at Barcelona.
He neutralised Pablo Osvaldo in a 2-0 win over Roma whilst winning back possession nine times.
While he's also aggressive, he's not thuggish like Pepe.
How does Andreu Fontàs play 15 more games for Barça than Alberto Botía?
Activating the buy-back clause for Botía would make sense.
Botía is a solid defender and I can only assume his passing is the reason why Pep Guardiola hasn't given the 23-year-old an extended run in the team.
This season, Botía has completed 67.3 percent of his passes but it would be higher if he played on a better team because the majority of his "passes" are clearances.
Mapou Yanga-Mbiwa has been a strong influence in Montpellier's ascent to the top.
However his teammate Henri Bedimo, an energetic left-back, has clearly been Montpellier's best defender.
There's a Ligue 1 centre-back that is better than Yanga-Mbiwa and ranked at No. 1 on this list.
Serdar Tasci played tremendously in a 2-1 loss to Bayern Munich last December.
Cristian Molinaro was sent off with an hour left to play and Bayern Munich had previously won 6-3 and 5-3, Tasci was firm as Bayern Munich only scored twice.
Tasci's passing is efficient and he has won 32 out of 44 aerial challenges this season.
Mateo Musacchio reads the game well which is why he has intercepted the ball 134 times.
It's not his fault that Cristián Zapata forgot how to defend.
If Villarreal do get relegated, then Musacchio is a must-buy because his transfer value would be cut in half.
I haven't seen enough of Dedé, so I'll defer to South American football journalist Tim Vickery.
Here's a compilation of his quotes regarding the highly touted Brazilian:
Dedé was badly missed shoring up the Vasco da Gama defence—October, 2011.
In defence Menezes has rectified a mistake he made in the Copa—Vasco da Gama's imperious young centre back Dedé should have gone to Argentina—August, 2011.
Right now Kyriakos Papadopoulos' thought process is tackle, tackle and when in doubt—tackle.
For someone so young, his positional awareness is elite, so he doesn't always need to go in with guns glazing.
From time to time, he gets burned and he puts Schalke at a disadvantage. However, numbers don't lie and he has won back possession 226 times in 29 Bundesliga games.
So he has taken the ball off his opponents 226 times and he's only 20 years old.
His long passing is underrated and whilst it isn't statistically impressive, I've seen him execute some great diagonal long balls.
His compatriot Sokratis Papastathopoulos is also looking good at Werder Bremen.
I see greatness in Willy Boly.
Physically impressive at 6'3", advanced understanding of the game, has the ability to shut down good forwards and is a capable tackler.
A fortnight ago against Paris Saint-Germain, Kévin Gameiro didn't even get off a shot because of Boly, who intercepted the ball six times.
In a 0-0 draw against Saint-Étienne, Boly dominated Pierre-Emerick Aubameyang, who couldn't get a shot on target.
In that game, Boly made four successful tackles.
It's a perfect situation for Barcelona because they have a world-class prospect who doesn't command a transfer fee disproportionate to his actual playing value.
Auxerre will probably get relegated, so he'll be dirt-cheap.
L'Équipe rate him as the third best defender in Ligue 1—massive accolade because he plays for the worst team in the league.
Please read Barça-Chelsea Observations.
Statistics courtesy of WhoScored.com.