ORLANDO — Before a teamwide slump led to a trade deadline sale, the Giants were quietly looking at potentially adding help at second base. Months later, they announced that incumbent Casey Schmitt underwent left wrist surgery, but president of baseball operations Buster Posey doesn’t sound like he feels adding at that position is still necessary. The Giants anticipate Schmitt being only about a week to 10 days behind at the start of camp, and they also have plenty of faith in Christian Koss. Tyler Fitzgerald, who entered last season as the starter, also still is on the 40-man roster. “We feel really good about the strides that Casey made last year, and I think Koss, too, had some big moments for us and for me is a guy that’s just kind of an all-around baseball player and can impact the game in multiple ways,” Posey said. “We’re very optimistic with both of those guys having a solid year under their belt and we know that there’s room for growth. I’ll just leave it at that.”There are multiple potential options on the trade market, including St. Louis’ Brendan Donovan and Tampa Bay’s Brandon...