I'm really surprised Mayer isn't seeded, given reached the QFs last year and at #33 that surely should have been enough to push him up into the seeding positions. Rosol just missed out as well.
The only bits that aren't random are that the 25-32 seeds will face the 1-8 seeds, and that the 13-16 seeded players face the 1-4 seeds.
So yeah, the odds of drawing any quarter-finalist are 1/4.
Murray's potential R3 opponents are: Paire, Dolgopolov, Anderson, Chardy, Dimitrov, Fognini, Benneteau, Robredo
Potential R4 opponents are: Haas, Tipsarevic, Almagro, Kohlschreiber
Paire would be good. Dolgopolov's form has been poor this year, so he'd be good too, if he made it that far. Dimitrov would be unlikely, in my view, to handle Andy in a best of five on grass, or anything else for that matter. All in all round three doesn't look too bad.
In the 4th round Tipsy's had a bad time hasn't he, so would he make that? Haas and Kholi stand out there for me, but I think Andy is better than both of them on the surface.
Ah well, soon see I suppose.