University of Northern Iowa baseball coach Rick Heller is recovering from serious injuries he suffered in a maintenance accident at the Panthers’ ballpark.Heller spent the night in the intensive care unit at Allen Hospital in Waterloo. U-N-I’s seventh-year skipper was working on the baseball diamond at Riverfront Stadium in Waterloo yesterday afternoon when he was struck by the tongue of a large, steel roller that’s used to pack down the infield dirt. Heller suffered multiple injuries, including a broken collar bone, several broken ribs, a bruised lung and a blow to the head. Witnesses say it appeared that Heller was briefly unconscious after the accident, but he was alert and aware of what had happened by the time the ambulance arrived.