Due to an influx of talent at the central midfield position and a lack of depth in defense, Pep Guardiola and Barcelona have used a 3-4-3 formation at times this season, instead of their normal 4-3-3. This is not foreign to the Clues - they occasionally used a similar setup in Guardiola's days - but it is quite different from their normal setup. Many Barcelona fans would like to see the setup in El Clasico against Real Madrid, and feel that it is the best way to break down Jose Mourinho's triovot of three defensive-minded midfielders.
However, Barcelona's best performance of the season in the 3-4-3 was all the way back in the first game of the season, against Villarreal. The Yellow Submarine's 4-4-2/4-2-2-2 played right into the hands of Barcelona's formation and their strikers were marked out of existence. There have been other high-profile games this season in which teams playing a back three have out-played teams playing with two strikers. It's just an inherent advantage when the two setups face off against each other. A back three has two defenders to mark the strikers and another to cover.
Unfortunately for Barcelona, Real Madrid will not be playing with two strikers. They will be playing with a lone center forward, flanked by Angel di Maria and Cristiano Ronaldo. They will both be cutting in from wide positions onto their stronger feet. This is, almost always, a disaster for teams playing three-man back lines to defend. Unless the defensive midfielder in the 3-4-3 drops into the back line and Barcelona is perfect in their transition between 3-4-3 and 4-3-3 without possession, it's going to be exposed.
This was certainly the case for Barcelona against Valencia, who played a 3-4-3 with Daniel Alves pushed up the pitch as a wide forward, instead of as a right back to start the match. Valencia's left-leaning 4-2-3-1 caused serious problems for the Cules in the first half, leading Guardiola to change his system. Barcelona got a draw out of that match, but only looked like the superior side after making a drastic tactical change.
If Barcelona starts with the 3-4-3, Mourinho will be pleased, because di Maria and Ronaldo will probably tear it to shreds.
We'll have live coverage of El Clasico from just before 4:00 p.m. ET, when lineups are released. For more on the two teams, head over to Real Madrid blog Managing Madrid and FC Barcelona blog Barca Blaugranes. Check out SB Nation Soccer and our El Clasico StoryStream for more in the build-up to the game. For more from around the world of football, follow @SBNationSoccer on twitter.