A stomach bug has swept through Phillies camp. On Sunday, it prevented Jonathan Papelbon from pitching and knocked Roy Halladay from the mound after one inning. And so Halladay’s curious spring continues. On Tuesday, the 35-year-old righthander complained of feeling lethargic after being battered and bruised by the Detroit Tigers. Sunday, he slipped out of the Phillies’ dugout and into the clubhouse after throwing just 25 pitches against the Baltimore Orioles. The first thought that raced through observers’ minds as Halladay left the field was that he was injured. His fastball has lacked zip for several starts now and there was the whole lethargy issue last week. All of this comes after Halladay spent seven weeks on the disabled list during a disappointing 2012 season. Halladay dealt with a sore back and a stiff shoulder last spring, problems he and Phillies officials denied at the time. This year, it’s only natural to wonder if there’s more to Halladay’s curious spring than delivery issues and a bad stomach. Phillies pitching coach Rich Dubee has been pressed on Halladay’s condition and says the pitcher is healthy. And he says he means it this year. Still, it was reasonable to ask whether there was more to Halladay’s exit Sunday? Charlie Manuel said no.