Walt Weiss didn’t look overjoyed Friday night. At least not for a manager who’d just seen prized rookie third baseman Nolan Arenado hit a walkoff homer, lifting the Rockies to a weird and wild 10-9 victory over the Padres. It’s not the fact that the Rockies blew two six-run leads before getting bailed out by Arenado’s heroics that concerned Weiss. Rather, Weiss was likely thinking about injuries to powerhouse outfielders Carlos Gonzalez and Michael Cuddyer. CarGo twisted his left knee in an at-bat in the sixth inning, aggravating a situation that’s been bothering him since spring training. CarGo said after the game that he plans to be on the field Saturday, but he was limping badly when he left the field Friday night. The injury forced Weiss to use Jonathan Herrera in left field — the first time Herrera has played the outfield in his pro career. Why Herrera? Because Cuddyer was unavailable because of what Weiss called a “rib strain.” Before the game, Weiss said Cuddyer was only “sore,” and said he was available for pinch-hitting duty if necessary. Clearly, there was more to the injury than just soreness resulting from a tumble Cuddyer took running hard to first base in the 12th inning Thursday night. “Strained rib” could mean an oblique injury, and that could be really bad news. Cuddyer, who’s having an all-star-worthy season, suffered an oblique strain last season on July 31 and played just three more games after the injury before his season was shut down. It seems as if an injury is the only thing that can slow down CarGo. He stroked two triples Friday, the second two-triple game of his career. Over his last 26 games, he’s gotten a hit in 15 of them, and in 13 of those 15 games he’s had multiple hits.