PHOENIX -- San Francisco Giants right-hander Johnny Cueto threw a bullpen session Saturday, and the team was encouraged enough for manager Bruce Bochy to say the club hopes Cueto can return toward the end of this season.

Cueto, who had major elbow surgery last August, was 18-5 in 2016 and selected to the All-Star Game, but he has since gone 11-10 in the past two years combined.

"I think he surprised a lot of us with where he's at," Bochy said before Saturday's game against the Arizona Diamondbacks. "It's all fastballs, but he's gotten himself in great shape, too. I think it's the best shape I've seen Johnny in, to be honest.

"From what you saw today, you've got to believe he's going to be pitching before the season's over. I'm not going to be surprised if he pitches in September."

Cueto threw off flat ground Saturday, and the hope is that next week he will throw breaking balls and changeups.

If Cueto comes back in September, it will be as a starting pitcher, Bochy said. Cueto, 33, has been a starter since breaking into the majors in 2008 with the Cincinnati Reds.

"I'm happy to be here and it's good to be around the guys and spend some time with the team," Cueto said in Spanish. "God willing, yes, I want to pitch in September. Right now, I feel really good."

Cueto said he has lost 20 pounds, down from 245 to 225 pounds, and would like to pitch at 230.

"I feel like a kid of 20, 25 years old," Cueto said with a laugh.