CHICAGO — In assessing Edward Cabrera’s injury history, the Chicago Cubs projected that his pure stuff and untapped potential would ultimately outweigh any health concerns. Between his natural talents and the organization’s pitching infrastructure, the Cubs believed they could unlock a top-of-the-rotation starter in the sweet spot of his career.Right now, that appears to be a miscalculation.It’s not that the Cubs particularly miss any of the three young players they traded to the Miami Marlins to acquire Cabrera back in January: Owen Caissie, Cristian Hernandez and Edgardo De Leon. It’s more the opportunity cost.A methodically built team that wins 92 games and a playoff round only has so many ways to improve. The farm system does not contain an endless supply of prospects. The budget for baseball operations is not unlimited.Amid a wave of pitching injuries, Cabrera walked off the Wrigley Field mound with an athletic trainer Tuesday night, exiting his start against the Colorado Rockies in the fifth inning of a 5-2 loss to the worst team in the majors.Which NL pitcher deserves to start the All-Star Game?Ken Rosenthal and Johnny SweetCabrera suddenly felt a cramping sensation on the palm side of his right hand while throwing a changeup, Cubs manager Craig Counsell explained.“All things considered, he’s good,” Counsell said. “It’s a cramp, right now, as far as we can tell. All the other tests are clean and negative. I think it probably scared him a little bit.”