Does Joba have a shoulder problem?

Over on Baseball Prospectus John Perrotto has a weekend roundup column (membership required) and in this week's he mentions something troubling about Joba Chamberlain (hat-tip to River Ave. Blues):The Yankees couldn’t move right-hander Joba Chamberlain from the rotation back to the bullpen if they wanted to at this time, because shoulder problems make it too difficult for him to warm up quickly.RAB's Ben K. wonders about the legitimacy of the rumor:If Joba had a known shoulder problem, the Yankees would not be trotting him out there every five days. They care too much about and are too focus on Joba’s future to risk his health in the short term. A shoulder problem, however, would explain the downward trend in fastball velocity Joba has been displaying since his August 2008 injury.If the Yankees are dumb enough to have Joba start with a shoulder problem then they might just qualify for dumbest organization on the planet. It's bad enough when you tell two pitchers not to w...