Royals manager Ned Yost thinks he has a tough bullpen, filled with relievers capable of throwing multiple innings on consecutive nights.

"We don't feel that they're soft. We don't feel like they're sissies," he said after Kansas City beat San Francisco 3-2 Friday night to take a 2-1 World Series lead.

Kansas City relievers combined for four hitless innings, becoming only the fourth bullpen to achieve the feat in the World Series and the first since Toronto in 1992.

Kelvin Herrera entered in the sixth, walked his first batter and induced three groundouts. Throwing at up to 101 mph, he walked his first batter again in the seventh, struck out Brandon Belt and was replaced by rookie Brandon Finnegan.

Herrera has thrown 59 pitches in two games over three days. Yost wasn't sure whether he would call on Herrera again Saturday.

"Look, we're in the World Series. Everybody is available, but we don't want to be stupid either," Yost said. "The one thing that we do really well as a staff is we communicate. Our relievers and our starting pitchers know that we have complete trust in them. If they tell us they can't go, we trust it."