Centre back required

Not sure who's going to be in the centre of our defence against Man United today. Collins and Reid are both out, so we have to hope James Tomkins will be fit. Reece Burke and new signing Doniel Henry are also injured and Guy Demel is doubtful too. So in a worst case scenario we could have Joey O'Brien at centre back alongside either Kouyate or Song. Doesn't sound good against Van Persie, Rooney, Di Maria and Falcao, though at least Sakho is available — he will probably replace the injured Carroll — and Kouyate is back from Africa. And there is always the outside chance that Big Sam will come out of retirement and play in the middle of the back your himself. Or maybe Mr Moon could do a job?