In his two frames Petit struck out one and induced four groundouts.
"Every time, I try to work on my command, especially the first two games," Petit said. "I don't work on velocity. I tried to start today working both sides of the plate and on the location of the ball."
Petit went 5-5 with a 3.69 ERA in 117 innings, the most he'd ever pitched, in 2014 and enters Spring Training having skipped winter ball for the second straight year.
Without having winter ball to get in shape, Petit said his velocity is not where he wants it quite yet, but that it should come later in the spring.
"I have to work more right now for velocity [to] come back," Petit said. "I know it's coming back."
Giants manager Bruce Bochy has said Petit will be available for spot starts throughout the year, but right now the right-hander is slated to begin the season in the bullpen.
"I'm waiting for my opportunity," Petit said. "I'm ready for any job they give me. Whatever they give me, I'm going to try to make it my job."
• The Giants reassigned right-handers Clayton Blackburn and Raymond Black, as well as left-hander Nik Turley, to Minor League camp.
William Boor is a reporter for MLB.com. Follow him on Twitter at @wboor. This story was not subject to the approval of Major League Baseball or its clubs.