In the post-Moneyball era, it’s become common for footballers to be judged predominantly on their stats in order to determine what they offer a team.
Come the final whistle, supporters and pundits will look to the number of shots a striker has had, the number of tackles a defender made or the chances created by a playmaker to assess contributions.
Yet looking at the stats this term, some may question why that is. For a playmaker—who by definition must create goals and chances for those around him—Oscar’s assists remain relatively low (two in all competitions) although he leads the Stamford Bridge scoring charts with five goals.
In comparison, Mata had eight assists at this stage last year, proving a lethal weapon in attack for Chelsea.
Both are similar players, but their roles for Chelsea are very different.
Whereas Mata is a player who demands possession and prefers to float in the middle, picking out teammates as he looks to carve open a defence, Oscar is equally as effective without the ball.
Like his Spanish teammate, Oscar will drift between the lines and make a mockery of pre-match line-ups, where TV producers will show him as playing in the centre of Chelsea’s attacking three in their formation graphics.
That may be the case on paper, but he operates outside the confines of a rigid formation. For instance, Oscar will often drift wide to receive possession, and in so doing allows for any one of Eden Hazard, Mata or Andre Schurrle to move infield and occupy space.
With Chelsea playing without wingers in the traditional sense, it’s a vital aspect of his game. It means Chelsea’s attackers are somewhat more difficult to pick up by their marker, who in some cases can be caught in two minds—does he mark the space or track the player?
At the highest level, such indecision can prove costly, and we’ve seen many times this term the impact Oscar has had in rotating his position.
It’s a role Mourinho discussed earlier this season, one that demands more from his players, which has been a key factor in Mata’s absence.
“I want to build with Oscar as my number 10,” he was quoted as saying by The Independent in September. “I want the other two players, from the side (wings), to adapt to that reality and to learn how to do things that they were not ready to do before.”
Referring to his preference to play Oscar over Mata, Mourinho had earlier explained that he sees the Brazilian as being far more versatile in a game.
“One thing is to play with Ramires and Oscar in the side, them closing (down) each side, and Mata as a number 10 behind a striker, to have clever assists and to have clever passes; fantastic actions because he has great talent,” he said. “Another thing is to adapt to the way we want to play.”
For all his talent, Mourinho sees Mata as restrictive, while Oscar allows the team to flow and operate in other areas.
Like Mata, who often looks to pick out the front man, whether that be Fernando Torres, Samuel Eto’o or Demba Ba, Oscar has demonstrated a good relationship with Branislav Ivanovic on the right side of Chelsea’s attack.
As the graphic above from Chelsea’s recent victory over Manchester City outlines, the Brazilian will look to bring those behind him into play, with Ivanovic’s attacking presence on the right flank a key aspect of Chelsea having some element of width.
Oscar rarely drops deep, preferring to influence play further forward. Interestingly, Chelsea's 2-0 loss to Newcastle United last week outlines how influential Oscar can be.
On a frustrating afternoon for the Blues, the Brazilian was forced to play more in the middle third (as shown below) given the Magpie's deep defensive line, and with Oscar more withdrawn from the danger areas, Chelsea's attacks were often blunt and carried little threat.
His role in this Chelsea team provides a good reason for his low level of assists, as it isn’t all about him. Like any effective No. 10, he is bringing others into play, developing attacks and stretching the opponent.
It’s all done with an unselfish tone, however, which is an endearing quality in any player who deals with the profile and pressures of being a No. 10.
That said, his five goals this term also outline the benefits Oscar has gained from his approach, playing his part in Chelsea’s build-up play to then be the man finishing off their attacks.
It doesn’t take a mind greater than the average football fan to understand that scoring goals wins matches. It’s a prerequisite, although away from his attacking instincts, Oscar has been taken under Mourinho’s wing for different reasons.
We’ve seen it throughout 2013-14, and on Wednesday evening against Schalke in the Champions League, Oscar’s defensive influence was there for all to see.
Chelsea’s opponents enjoyed the better of the early exchanges in what was another disjointed Blues display on the back of their defeat to Newcastle United last weekend. They won the game 3-0, however, with Oscar a major reason for Chelsea eventually taking control of proceedings.
Unlike previous seasons—and his first spell in charge—Mourinho’s Chelsea are putting a significant emphasis on pressing teams higher up the pitch. It’s not exactly at the levels we've grown accustomed to with Barcelona, but it’s a clear tactic nonetheless.
Oscar has been the focal point of this approach, and against Schalke he was often the furthest man forward, pressing the centre-backs and making them uneasy in possession. It’s at moments in a game such as this that he reverts to a more central role, working tirelessly in a way we haven’t seen the likes of Mata do.
Perhaps Mourinho saw how effective Oscar proved to be in Chelsea’s 2-2 draw with Juvenuts last season, with the midfielder scoring twice in a game in which he denied Andrea Pirlo the space to operate, shackling his ability to control Juve’s tempo.
Mourinho has put a considerable element of trust and expectation on the 22-year-old Oscar’s shoulders, yet the signs suggest he is more than up to task.
Garry Hayes is Bleacher Report's lead Chelsea correspondent and will be following the club from a London base throughout the 2013-14 season. Follow him on Twitter here @garryhayes