Washington center fielder Denard Span had surgery Monday to repair a right core muscle injury and will miss the Nationals' opener next month. Manager Matt Williams said the projected time for Span's return is uncertain and added ''you're looking at four-to-six weeks before he can start doing baseball activity again.'' Span had surgery to repair a sports hernia injury in December and reported discomfort at the start of spring training, which he attributed to offseason training. He went 1 for 2 in the Nationals' spring training opener on March 5. More...