Here's the rule, for those that are interested, out of the ATP rulebook:
B. Singles Qualifying
1) Direct acceptances shall fi rst be selected from players who sign in with the highest
position on the most recent Emirates ATP Rankings list, including a protected
2) If there are still places available for direct acceptances in the qualifying draw, the
next players selected shall be those with the highest position on the most recent
Emirates ATP Doubles Rankings list.
3) If there are still places available, the tournament shall be awarded additional wild
card positions equal to the number of places available. The tournament may, at its
option, choose to fi ll all, or some, of those places with these additional wild card
4) There shall be an alternate sign-in list comprised of players that sign in who are
not selected as direct acceptances. In the event that direct acceptance players
are not present for fi rst-round qualifying matches or if players are moved into the
main draw from the qualifying (before the fi rst ball is hit), players shall be selected
from the alternate sign-in list in the order described in sections 1), and 2) above.
Alternate sign-in deadline is 9:00 pm local time the day before the start of the
qualifying. Thereafter, the deadline is one half (1/2) hour before the fi rst scheduled
match each day an Alternate may be required.
5) Any vacancy created by the withdrawal of a seed, after the qualifying draw has
been made but prior to the release of the order of play for the fi rst day of the
qualifying event, shall be fi lled by the next highest positioned player or team in the
qualifying draw eligible to be seeded. The position vacated by that next highest
positioned player or team shall then be fi lled by the next eligible player or team on
the qualifying draw alternate list.
All Ranked Players Have Been Accepted and...
Case: The tournament has elected not to use their wild card allocation
to fi ll the qualifying draw with unranked players. Are they eligible
to sign in as alternates?
Decision: No. Unranked players are only allowed into the draw as a
wild card selection.