Pirates starting pitcher Jeff Karstens likely will start the season on the disabled list with a shoulder injury, meaning the four pitchers who were fighting for the final spot in the starting rotation are fighting for two spots. Karstens was scratched from a scheduled start Sunday after he told the team early in the morning that his shoulder was bothering him again, general manager Neal Huntington said. "He felt like he couldn't pitch," Huntington said. Karstens has been battling the injury -- officially right biceps tendinitis -- since Feb. 18, when he missed a batting practice session. He started throwing batting practice earlier this month and made two starts in minor league games at Pirate City, most recently a week ago throwing 50 pitches. The Pirates were leaning toward making Karstens the No. 4 starter, though any setback would have jeopardized his scheduled season debut April 7. "We still don't know the long-term prognosis," Huntington said. "We don't even have a really good short-term or moderate prognosis. We're working through that as we speak." But Huntington said it is "most likely" Karstens starts the season on the disabled list, what would be his second trip to the DL in as many seasons. "We've got to shut him down and take it one step at a time," manager Clint Hurdle said. "It takes him out of the picture to start in the opening. That's about all we've assessed." The Pirates non-tendered Karstens, who was eligible for arbitration, in part because of injury concerns. Karstens spent more than two months on the disabled list -- leaving a start early with right shoulder tendinitis and later sustaining a hip flexor injury in a rehabilitation start. Read more: http://www.post-gazette.com/stories/sports/pirates/pirates-pitcher-karstens-headed-to-dl-with-shoulder-problem-680787/#ixzz2OYwuC1YG