When registration for the 2013 Boston Marathon re-open on Monday morning, there were roughly 10,000 spots open for runners with qualifying times, reports Runner's World. That means that about 12,000 runners who deferred from the heat-waved 2012 race or had qualifying times at least five minutes better than the new, tighter time standards registered last week.

Registration for the 2012 race wrapped in two weeks, albeit with the old, looser time standards. In 2011, before the Boston Athletic Association moved to the phased registration, the race sold out in eight weeks.

If all remaining spots are claimed by Friday at 5 p.m. ET (with confirmed qualifying times), BAA will give bibs to only the fastest qualifiers in that set. It remains to be seen where the cut-off will land. If there are still openings remaining at the close of registration on Friday, the race will re-open Monday on a first-come, first-serve basis. Runners who register at that point must still have a qualifying time to get a bib.