I also see Rashid as the obvious "young prospect" for the Sri Lanka tour: he'd be a handy net bowler and could learn a lot... and if half the team went down with a bug he's good enough to be called upon.

I'm also expecting Flintoff to play in Sri Lanka alongside 2 further seamers (Hoggard and Sidebottom) plus Panesar. Giles is an automatic if fit... but if (as you suspect) he is not then options for the other spinner might be:

1. Pietersen and Vaughan (batsmen, occasional bowlers)
2. Dalrymple / Yardy / similar (bits n pieces players)
3. Batty or similar (bowler who can bat well against spin and can play Murali ok)
4. Another specialist spinner...

One major consideration: they have to have a plan 'B' for the scenario in which Flintoff is unable to play. This might warrant a 3rd specialist seamer... meaning that a second specialist spinner was out of the question. Using Pietersen and Vaughan (and the odd over from Collingwood) might be the obvious solution... and Rashid could figure (promote the wicket-keeper to 6 and play Rashid as a no 7 batsman who bowls)... but this scenario might swing the selectors in favour of Dalrymple / Yardy.