Transfer rumors have been flying lately, and one of the common questions which I see asked on this site is "how does player x work in our formation"? While this is certainly something to be considered, I think this question should be relatively secondary in comparison to what skills and traits the player brings. Whether or not Oscar could fit into the double pivot of a 4-2-3-1 will certainly have some impact on his minutes in the early going of the season, but the reality is that formations will be altered to get the best talent on the pitch. Don't agree? Just look back at what the managers have done during the Roman Abramovich era at Chelsea*.
*I use only the Abramovich years as this was the only period in which the club has worked with the type of resources we have available now. In 1999 there was just no chance we'd have this sort of signing power. I also ignored Ranieri, as he was there pre-Abramovich and was dumped ASAP by the owner.
Roberto Di Matteo took over last March. As we all saw, his primary formation was the 4-2-3-1. So what should we read into this? My answer is nothing. Di Matteo took over a team using a 4-2-3-1 and didn't have a transfer window to work with. The fact that he didn't dramatically alter basic tactics mid-season shouldn't be a reflection on what he plans going forward. It's also worth noting that his 4-2-3-1 was a bit different form his predecessor's, as he played a much deeper defensive line and the wide players were set up much deeper in general. There is absolutely no guarantee that we're even going to be lining up in a 4-2-3-1 to start this coming season.
Di Matteo took over for Andre Villas-Boas, who started the season using his 4-3-3 high press from Porto. As the season progressed, AVB moved this 4-3-3 deeper before eventually altering it to a 4-2-3-1 shape. Prior to AVB we had Carlo Ancelotti who brought us the 4-4-2 diamond. The diamond switched to a 4-3-2-1 for a bit before reverting to the old reliable 4-3-3 for the run in. His 2nd season started as a 4-3-3 before switching to the diamond after the signing of Fernando Torres. Towards the end of that season, we saw the 4-3-3 more often again.
Going even further back, we had Scolari. What formation didn't he use? We saw 4-1-4-1, 4-3-3, 4-2-3-1, and 4-4-2 combinations regularly. He may have even run out a Christmas tree at some point, I honestly can't remember. When fired mid season, Guus Hiddink brought back some stability with the 4-3-3. Like Di Matteo, though, it's hard to read too much into a 22 game stopgap who didn't have the ability to add to the squad.
That brings us to Jose Mourinho. Jose brought us consistency over the duration of his span at Chelsea. We pretty much ran a 4-3-3 out there every game. Interestingly enough though, Jose has changed primary formations basically every time he's switched clubs. Do you think his basic philosophies have changed, or do you think he may simply be finding a way to get his best players on the pitch and play to their strengths? He's won silverware everywhere he's been, so it's hard to argue with his approach.
Chelsea may well start the season in a 4-2-3-1. Some of their younger buys may not be best suited for any available role in that system. These 2 things should never be reason to avoid a buy of a young talent though. When considering an older player that will likely only play for a season or 2 here (Maicon?), formational fit is hugely important. A player the age of Oscar or Eden Hazard may well see dozens of different formations in their time at Chelsea if they transition to the Premier League in the way we hope they will.
When Michael Emenalo is evaluating young talent, he really needs to ignore where they fit in the formation they use right now and focus instead on what he thinks they have the ability to become. Ask yourself this...if you were running a 4-2-3-1 in 2001 and buying players to fit that system specifically, where would Frank Lampard have fit? Do you think you'd be kicking yourself for passing on him 558 appearances and 186 goals later? The best managers in the world select the formation they will use to maximize the talent available to them. They don't ignore talent because they want to play a specific system.
Di Matteo won the Champions league with Chelsea because he adjusted what he was doing to fit the players he had available. AVB was fired (in large part) because he ignored what his players could do well in favor of using a very specific formation. We know Robbie is willing to do whatever works best with the talent he has in order to win, so why shouldn't we simply focus on giving him more talent? If he's worth keeping around for the long term, he'll find a way to make it work.