Cain, who underwent elbow surgery last August for removal of bone chips and spurs from his throwing arm, mixed fastballs, changeups and curveballs during his 40-pitch stint. He rested about midway through his outing and appeared to throw even more freely when he returned.
"It seemed like it was coming out a little bit harder," agreed Buster Posey, who caught Cain. "It was a nice, smooth thing."
Posey observed that Cain never grimaced -- a pained expression that often crossed the three-time All-Star's face last year as he unleashed a pitch.
"I think the main thing I noticed was it just seemed much more effortless than last year," Posey said of Cain's workout.
Due to his injury, Cain might not develop into game-ready shape as quickly as other pitchers. But he's still expected to be in the season-opening starting rotation.
"The ball definitely feels like it's coming out a lot easier," Cain said. "I feel like I'm not going to have to muscle the ball down to the plate or search for everything."
Chris Haft is a reporter for MLB.com. Read his blog, Haft-Baked Ideas, and follow him on Twitter at @sfgiantsbeat. This story was not subject to the approval of Major League Baseball or its clubs.