Once the top choice out of the Giants’ bullpen, Ryan Walker was optioned to Triple-A for the first time since he was called up in 2023 after struggling to get a foothold in the 2026 MLB season. Speaking to reporters Sunday, manager Tony Vitello outlined what Walker needs to work on to return to form.“I know he put in his work in the offseason, but your mind has a lot to do with everything,” Vitello explained. “And I think the biggest thing is making sure, whether it’s him or our team; you’re feeding your narrative that you want to choose to feed yourself every day, which is really challenging, especially at this level.  “So, mentality, I think, is the key.” In his last outing in Saturday’s 13-3 loss to the Pittsburgh Pirates, Walker allowed two earned runs on three hits and issued a walk in just 2/3 innings pitched. What was just a one-run deficit turned into three runs quickly. His ERA ballooned to a dismal 6.46 over his 16 appearances this season. Despite Walker’s struggles,...