[whatisthebluepill]

Does ATP use a different rule than ITF/Slams? Or why didn't Tsonga (as #5/next highest seed) get Roger's spot in the draw, and Robredo get Tsonga's former spot?

As it stands now, two of the (now) top four seeds are slated to meet in a QF.

Yes, they have different rule. Here the rule that was apply in this case. Robredo " the
next highest positioned player eligible to be seeded" took Federer's place, and a lucky loser took robredo's place

If a seeded player or team withdraws after
the main draw has been made but prior to the release of the order of play for the
first day of main draw, the vacancy created by the withdrawal of a seed shall be
filled by the following method:


a) 16/24 (Doubles)/32/48/64 96 and 128 Draw. The vacancy shall be filled by the
next highest positioned player or team in the main draw eligible to be seeded.
The appropriate lucky loser shall fill the remaining vacancy.
b) 56 Draw. If the vacancy involves a seed #1-8, then seed #9 moves to the vacated
seed position and the next highest positioned player or team in the main
draw eligible to be seeded shall be placed in the position vacated by the #9
seed. The appropriate lucky loser shall fill the remaining vacancy.
If the vacancy involves a seed #9-16, then the next highest positioned player or
team in the main draw eligible to be seeded shall be placed in the vacated seed
position. The appropriate lucky loser shall fill the remaining vacancy. source: atp rulebook http://www.atpworldtour.com/Corporate/Rulebook.aspx 7.20 E