Image source, Reuters

Sergio Aguero and Vincent Kompany are not the only high-profile absentees for Manchester City tonight. The Blues are also without the powerhouse presence of Yaya Toure. Gulp.

The Ivorian is still suspended after being shown a red card for lashing out at CSKA Moscow's Roman Eremenko last month.

BBC Radio 5 live

Mark Pougatch is about to get proceedings under way from Rome on 5 live Sport.

He'll be joined by commentator John Murray with former Republic of Ireland winger Kevin Kilbane summarising from the Olympic Stadium.

Alistair Bruce-Ball will also be live at Stamford Bridge with regular updates from Chelsea v Sporting Lisbon.

How are you feeling City fans? Nervous? Excited? Optimistic? A mixture of all three? Don't bottle those feelings up. Share them with us.

Tell us your pre-match thoughts, particularly how you think the Blues will fare without Sergio Aguero? Who are you pinning your match-winning hopes on instead?

For those who are not of a City persuasion, don't feel left out. We want to know your memories of past occasions when a team has sealed the result that they needed without their best player(s).

For example, Manchester United winning the 1999 Champions League final without Roy Keane and Paul Scholes (sorry City fans). Tweet using #bbcfootball, text 81111 or post on our Facebook page., external Go, go, go!

Sporting Lisbon need a draw to guarantee the runners-up spot ahead of Schalke - managed by the man who guided Chelsea to Champions League glory - Roberto Di Matteo.

Jose Mourinho has made six changes to the side which lost 2-1 against Newcastle on Saturday and has rested the likes of Willian, John Terry and Eden Hazard.

Among the substitutes is 18-year-old midfielder Ruben Loftus-Cheek.

Chelsea XI: Cech (c), Azpilicueta, Zouma, Cahill, Filipe Luis, Mikel, Matic, Schurrle, Fabregas, Salah, Diego Costa.

Sporting Lisbon XI: Patrício, Maurício, Oliveira, Silva, Esgaio, Carvalho, Mário, Silva, Slimani, Capel, Carrillo.

While our focus will be firmly on the shenanigans in Rome, Premier League leaders Chelsea are also in action. The Blues are already safely through into the last 16 and are guaranteed to finish as Group G winners, no matter what happens against Sporting Lisbon tonight.

We will have a dedicated live text commentary on the Stamford Bridge clash starting at 19:30 BST.

Former England left-back Ashley Cole is missing from the Roma squad, who are captained by veteran forward Francesco Totti.

Roma starting XI: De Sanctis, Yanga-Mbiwa, Nainggolan, Ljajic, Totti, Maicon, Pjanic, Keita, Holebas, Gervinho, Manolas.

Image source, Reuters

Of course, Vincent Kompany is not the only big name missing from that City team-sheet. Manuel Pellegrini was not able to scribble down 'S.Aguero' either.

And Sergio Aguero probably wasn't the only one in tears when he limped off at the weekend., external

Thousands of City supporters, and even Pellegrini, could be forgiven for going all misty-eyed as their Argentine talisman disconsolately trudged off the Etihad pitch against Everton.

First was the realisation they would be without their star player in Rome. Then, came the confirmation.

"He will be out for four to six weeks," said a grimacing Pellegrini.

Uh oh. Vincent Kompany is not playing for Manchester City and is is not even fit enough for the bench. But Spain midfielder David Silva does pass a late fitness test and is named among the substitutes.

City XI: Hart, Zabaleta, Demichelis, Mangala, Clichy, Fernandinho, Fernando, Navas, Nasri, Milner, Dzeko.

Image source, @ASROMA

Here's a sight that will please Manchester City fans - Blues skipper Vincent Kompany having a word with his Belgium mucker Radjo Nainggolan, who plays for Roma, as the two teams check out the Olympic Stadium pitch.

Kompany has been a doubt with a hamstring injury - does this picture mean that he will start? All will be revealed very shortly...

BBC Radio 5 live

And if that isn't clear enough, BBC Radio 5 live have produced this handy graphic.

In return for making our lives easier with this, the least we can do is make you aware that you can listen to their excellent coverage while you follow the live updates on this page.

Mark Pougatch presents from the Olympic Stadium at 19:00 GMT, so click on the 'Live Coverage' tab on this page later to get all the build-up to tonight's match.

Tonight, things are simpler for Pellegrini and City. Sort of.

City know they will reach the Champions League last 16 if their result is better than CSKA Moscow's result at Bayern Munich. Apart for one exception.

So a City win, coupled with a CSKA draw, would see City go through.

A City draw, coupled with a CSKA defeat, would see City go through.

But here's the twist. If CKSA lose and City draw 0-0, then Roma would progress.

Clear?

Image source, Getty Images

But I'm not alone. Mathematics can muddle even the sharpest of footballing brains - just ask Manuel Pellegrini.

Number crunching is a necessary skill for those involved in the Champions League group stages. Players, managers and coaches all frantically try to work out whether they have done enough to qualify.

City boss Pellegrini was left scratching his head over a permutation poser this time last year. Unfortunately he got it wrong, City ended up drawing Barcelona in the next round and the Chilean earned himself a dose of double maths as punishment.

Image source, Getty Images

I realise I might be in a small minority here. But I actually enjoyed Maths lessons at secondary school.

Whether it was simplifying expressions in algebra, or using Pythagoras' theorem (he's the bearded Greek bloke above) to work out the length of the hypotenuse, it was all good fun.

However, there was one thing I could not wrap my head around. Permutations....