Do you guys reckon Sturridge has been 'fit enough' for a while, but was given an extra week or two to get closer to 100%? You'd never have been able to tell he'd been injured for a while when he came off the bench at Stoke. The joys of having 2 quality strikers, I guess. If only we could have done the same for Torres
No. There are many different types of injury and each one has different recovery periods and different returns. Some injuries players will be out for a short while but return like nothing happens, over times it can be weeks of struggles and recurring injuries.
As for the Chel - ManU result, I'll say that for Liverpool it's honestly pretty much meaningless. Chelsea have just signed a midfielder for 20mil, they already had great depth and Mourinho has always been very good with rotation, there's on chance they don't improve on their points tally in the second half. Liverpool would have to pretty much win every game to overtake them. Arsenal will probably fall back once injuries catch up with them, but not City or Chelsea.
Utd, they simply are not a top 4 threat at this point in time. They could make some serious signings at the end of the window, but if they don't they are about as dangerous as Newcastle or Southampton. They can catch up with Liverpool if the club really slows down due to some crisis, but even then it will just be Everton taking the 4th spot.