LONDON (AP) -- First a ban. Now a bad leg. Just getting to London has been difficult for LaShawn Merritt.

Now that he's here the question is whether he will be healthy enough to defend his Olympic 400-meter title.

Merritt, who returned to track last season after serving a 21-month drug suspension, is a heavy favorite in the event that starts Saturday.

Or at least he was before hobbling off the track two weeks ago after tweaking his left hamstring in a tuneup race.