History says that unless your four bowlers include names like Marshall, Holding, Warne or McGrath, you need five. England need five. The difference on the speedgun at the Wanderers between Anderson and Broad and Morkel and Steyn was telling. England's bowlers were knackered, and the resting of Onions actually made sense, even if there's a debate to be had over his replacement.*
The solution must lie with five batsmen. Six makes it too comfortable, too easy to phone it in for a match or two. Which five should now be the puzzle, starting in Bangladesh. My money is on Ian Bell opening with Cook... You read it here first.
* Matthew Hoggard must have been looking at Sidebottom's speedgun readings with a wry eye. Steve Harmison - from memory the last England bowler before Sidebottom to puke on the pitch - must be pondering his big red face. So what hold does Siders have over the selectors? He even gets to bat above Jimmy Anderson, which is an interesting choice, to say the least.