Because Jessica Hardy's positive drug test was reported three days after an arbitrary roster deadline, the U.S. Swim Team wouldn't be allowed to fill her vacant spots in the 50 freestyle and 100 breaststroke with the next-fastest American swimmers. (Hardy has not yet been officially banned from Beijing.) Instead, the swim team will have to use women who were already on the final Olympic roster, which was due July 21.
The timing is especially unfortunate for Lara Jackson and Tara Kirk. They're the two swimmers who finished third at Olympic Trials in the 50 freestyle and 100 breaststroke, respectively, and would have gone to Beijing had Hardy's test come back a few days earlier (or, theoretically, had Hardy not been cheating).
While the hardened July 21 deadline seems capricious and arbitrary and surely could be tweaked with these extenuating circumstances, the U.S. swim team won't suffer too much because of Hardy's ban. The next two fastest American swimmers who were already going to Beijing would replace Hardy, and each was pretty close to making the Olympics in that event anyway (both finished fourth at Trials).
Kara Lynn Joyce (already on the team as a member of the 4x100 freestyle relay) will fill the spot in freestyle. She finished just .08 seconds behind Hardy at the trials in that event. In the breaststroke, Rebecca Soni (who qualified originally in the 200 breast) will get the nod. Soni finished fourth at trials in the 100, but was only .30 seconds away from second place.
Of course, this all presupposes that Hardy will lose her appeal. While the USOC is trying to clear up that mess, maybe somebody can figure out why it took 18 days for Hardy's drug test to come back. If the lady at CVS can see whether I have strep throat in under three minutes, surely the anti-doping agencies can speed-up their testing turn-around times.