Per 620 WDAE, Rocco Baldelli has an unknown muscle disorder and will be placed on the DL indefinitely. Rocco visited doctors all over the country who performed a slew of "invasive" tests on him but couldn't trace the cause of his muscle fatigue, which is what is limiting his play -- according to Rocco, doing simple workouts would leave him exhausted. Ruled out with the tests were some very serious conditions such as cancer, multiple sclerosis, Lou Gherig's disease.
When asked about Rocco's upcoming option, Andrew Friedman said that as of now it looks like they won't pick it up unless something happens between now and that day.
Update(12:20):(Kevin Gengler) Per Lancaster: