There were certain things manager Kirk Gibson expected out of his team heading into the season, areas in which he figured the Diamondbacks might struggle. Protecting leads late in games was not one of them. “I don’t think anybody thought this would be one of the things we (wouldn’t) do well in the first month,” Gibson said. “But it is. It’s a fact. We’ll try to clean that up.” Except for left-hander Matt Reynolds, none of the Diamondbacks’ late-inning relievers have been immune to struggles in recent weeks. Closer J.J. Putz and setup man David Hernandez have given up key home runs while right-hander Brad Ziegler and lefty Tony Sipp have surrendered game-winning hits. The Diamondbacks’ bullpen didn’t blow any leads in Friday night’s 7-6 loss to the San Diego Padres, but two relievers allowed runs that wound up being critical. Right-hander Josh Collmenter was charged with two runs in 1 1/3 innings while Ziegler allowed a run on two hits in two-thirds of an inning. After Gerardo Parra’s three-run home run in the top of the ninth inning turned a 7-3 deficit into a one-run game, the runs the bullpen allowed turned out to be costly. While Diamondbacks relievers have a solid 3.26 ERA, they have also served up 12 home runs and have blown a league-worst 10 save opportunities.