I think she was injured, but it only seemed to affect her serve. She seemed to move well and be able to execute other shots. Maria fans, and Maria herself, might have been skeptical, because of when the five minute injury break was called, and the fact that she seemed to do everything except serve just fine.
They may also be skeptical because of Serena's long history of claiming injuries.
LIke it or not, she is one of the most often injured players on tour and has failed to finish matches before, pulling in third sets when behind. This time, she toughed it out,but you can't blame Maria for being a little skeptical.
And it is time for Serena to show a little more maturity and start giving a little credit to her opponents. She simply got out played at Wimbledon and to pretend it was all about her not showing up is simply nonsense. Sharapova is obviously a tough match up for her, end of story.