SAN FRANCISCO — After Trevor McDonald’s latest eye-opening performance in the big leagues, Giants manager Tony Vitello said he wasn’t sure what the next step would be for the right-hander.“We’ll see what everybody’s fate is come tomorrow and the next day and the next day,” he said of the pitching decisions.Tomorrow brought a return to Triple-A for McDonald, who allowed just two hits and struck out eight over seven one-run innings Monday. The move was not really a surprise, as the Giants want to keep McDonald stretched out as a starter, and right now they don’t have an opening in their rotation. He was optioned to open a spot for reliever Joel Peguero, who had finished his rehab assignment. Vitello said the staff wants both McDonald and Blade Tidwell to be available as starters. Tidwell showed promise when he spent some time in the bullpen last month, but he also is back in Triple-A. The two right-handers, along with lefty Carson Whisenhunt, are the next line of defense for the rotation.“Those guys will be ready to go,” Vitello said.Vitello said he spent some time with McDonald well after...