What will Sporting do without captain Adrien Silva?

Sporting CP are set to be without captain Adrian Silva for their crucial UEFA Champions League Group F double-header against Borussia Dortmund after the midfielder underwent knee surgery, leaving the Lions without the man that makes their game tick with his creativity and fighting spirit.

The 27-year-old is out for four to six weeks, meaning he will not face Dortmund in Lisbon on 18 October or Germany two weeks later. Crucial to Sporting's fine Liga campaign last season and Portugal's UEFA EURO 2016 triumph, Adrien's influence for Jorge Jesus's team has been even more obvious this term.

What Sporting are losing
Just look at his numbers. Adrien might have only one goal to his name – the winner in the 1-0 Liga victory at Paços de Ferreira on 20 August, but his presence has been bolstered the defence as well as attack.

He has started all nine of Sporting's games this season and in the 702 minutes Adrien has spent on the pitch they have conceded four goals. In the other 108 they have let in seven, one every 15 minutes compared to around 175 minutes with Adrien playing.

Sometimes that has not mattered, such as against Estoril on 23 September when a 3-0 lead turned into a 4-2 win following Adrien's withdrawal. But nine days earlier the captain was replaced 73 minutes into their UEFA Champions League opener at Real Madrid with Sporting 1-0 up; they lost 2-1. Last Saturday the Lions were 1-0 up at Guimarães when Adrien was injured; even though they extended the lead to three it finished 3-3.

But it is in Europe where Adrien will be most missed. While domestically the midfielder will miss games like the Portuguese Cup tie with second-tier Famalicão or Liga matches against mid-table Tondela, Nacional and Arouca, the fixtures against Dortmund are likely to decide Sporting's UEFA Champions League fate.

It was a moment of brilliance from Adrien that gave Sporting their goal in Madrid and he also produced an assist in the 2-0 defeat of Legia Warszawa that moved the Lions to within one point of the top two.

Alternatives for Jorge Jesus
Elias – brought back to the club this season as a back-up for Adrien – scored at Guimarães after replacing the skipper, but the experienced Brazilian international's form has been patchy.

Adrien's place might, therefore, be occupied by versatile midfielder Bruno César, who this season has already played at left-back, central midfielder, on the wing and as a second forward.

Other options, like new recruits Radosav Petrović (who has only played three minutes this season) and Marcelo Meli (yet to make his debut), lack match fitness, and it is the same for young Brazilian midfielder Bruno Paulista.

One thing is certain: without Adrien there will be more work for midfield partner William Carvalho, who will take the armband during his captain's absence.