Even with an otherwise full strength squad, Roberto Mancini would have wanted Yaya Toure available for this game. He was the man who decided the previous FA Cup meeting between these two sides, when he intercepted a stray pass from Michael Carrick at Wembley in April last year, before firing past Edwin van der Sar for the only goal of the semi-final.

That summed up how the game was contested - United wanted to cool the tempo and play sideways balls to retain possession, City were about muscle and drive. But Manchester City's appeal to the Ivorian FA, that the Toure brothers should be allowed to play the Manchester derby before departing for the Africa Cup of Nations, has fallen on deaf ears.

To compound the problem in the centre of the pitch, Gareth Barry's red card in the comfortable 3-0 win over Liverpool in midweek leaves Mancini with a headache in midfield, to the point where he's protested about his lack of options in that zone, and wants to dip into the transfer market again.

That may amuse some considering City's spending in recent years, but the midfield battle has been particularly important in this fixture over the past 18 months. In addition to the FA Cup semi, there was the 0-0 at the City of Manchester Stadium in November 2010 when the midfields stood off each other and created a static game. Then there was the 2-1 win for United last February when Paul Scholes got space and dictated the game from deep, and finally the thumping 6-1 for City in October when James Milner and David Silva came off their respective flanks to dominate in the channels. One way or another, the midfield battle will be crucial here, and Mancini is right to be concerned.

The absence of both Toure and Barry means Nigel de Jong will be a certain starter in a deep-lying role, and he will probably be joined by Milner in the central midfield position he likes to play in. Pablo Zabaleta would be another option, but he and de Jong would be an unnecessarily cagey combination against a side that lack a true attacking midfielder, whilst Samir Nasri is more likely to be played on the flank, and asked to drift in and dominate the centre ground, with Silva doing the same on the opposite side.

If Milner does play on the flank, however, he'll be a good shout at 18.0 for first goalscorer - he's generally had good games against United, and his excellent penalty against Liverpool might mean he jumps forward in the queue to take one here, though Sergio Aguero and Mario Balotelli have also taken spot kicks successfully this season.

But what of United's midfield? Having been overrun against Newcastle in midweek, Ferguson might want to strengthen the centre of the pitch with an extra man. He's rarely played a five-man midfield so far this season, but did so in United's only trip to a current top six, away at Anfield. There, Phil Jones was used high up the pitch in midfield.

After Jones' poor display against Newcastle, I think Ferguson might consider pushing him into midfield again, perhaps alongside Michael Carrick and Anderson, in a midfield that can match City for mobility. That would mean no Ryan Giggs and no Dimitar Bebatov upfront, with Wayne Rooney possibly being used as a false nine, up against Vincent Kompany. He seems to cause the Belgian problems with his positioning, pulling him out of the backline.

The battle on the wings will be about a contrast in styles - City's will come inside, United's will stay wider and stretch the play. But it's in the middle where this game will be won and lost - and with both managers lacking options in that zone and likely to be more cautious than a neutral would like, I'm going to back under 2.5 goals at anything over 2.0.