Orioles second baseman Brian Roberts is expected to miss most of April with a sore back. The leadoff hitter probably won't be ready to return when he's eligible to come off the disabled list on April 25. He is dealing with a strained abdominal, which jarred his ailing back. He missed all but six games of spring training with the back issue. "It probably irritated some nerves in areas of the lower back, which caused now the abdomen to hurt again, the back to flare up again," Orioles manager Dave Trembley said.