"Now, we have to deal with the solution," manager Dusty Baker said.
The solution for Game 4 on Wednesday was Leake, who made 30 regular-season starts with a 4.58 ERA but was left off the Reds' initial postseason roster because the five-game NLDS, on paper, necessitates only four starters.
Leake suddenly becomes key to the Reds' hopes of reaching the World Series. By rule, Cueto, sidelined by a right oblique strain, is ineligible to pitch in the best-of-seven NLCS should the Reds advance, an edict put in place by Major League Baseball to prevent teams from tinkering with their rosters mid-series.
"The show goes on," right fielder Jay Bruce said.
Bruce noted that the Reds won the NL Central with their share of injuries. The most significant was the July loss of star first baseman Joey Votto to a left knee injury that sidelined him until early September and has sapped his power. In that case, left fielder Ryan Ludwick stepped up to fill the production void.
"It's a tough loss. It is. [Cueto] is our guy," said rookie Todd Frazier. "You wish the best for him, because whenever he's out there, it's relaxation [for the rest of the team]. It's going to be hard, but we've been through it with injuries. People have to step up, and our pitching staff has done it all year.
"We're not really worried at all."
Frazier found out about Wednesday's roster move while watching television. Shortstop Zack Cozart was surprised by the news because he did not know the injury was to Cueto's oblique.
Earlier in the week, the Reds were calling it back spasms, a much less sinister diagnosis.
"It's obviously not good news," Cozart said. "We have faith in Leake. Homer [Bailey] stepped up big time. We've got a good pitching staff that we're confident in. Obviously, not having Johnny, our ace, is going to be tough. But we're going to step up, score runs, pitch and play good defense."
Said catcher Ryan Hanigan: "It's tough, but it's probably smart. I don't think there's any other way to do it. From what I'm gathering, it's the type of thing where [Cueto] could have hurt himself worse. You have to do what's best for the guy first, in terms of his health."
These are uncharted waters for a team that made it through the entire regular season with each starting pitcher making every start on schedule. Cueto, Bronson Arroyo, Mat Latos, Bailey and Leake started 161 of the Reds' 162 games -- the exception an Aug. 18 Major League debut for right-hander Todd Redmond in Game 2 of a doubleheader at Great American Ball Park.
Pitching coach Bryan Price chalked it up to "good fortune, good luck." Maybe. If that's the case, then it was pure coincidence that Price had a similar stroke of luck with the 2003 Mariners, the most recent team to employ only five starting pitchers all season.
"When [the Cueto injury] happened the other day, that was devastating at the moment," Baker said. "But you have to get over that and realize, 'Hey, we've got more games to play.'"
Those games begin Wednesday with Leake's first postseason appearance.
"Johnny is a big part of our team, but we're going to have to find a way [to move on]," Hanigan said. "Maybe it will inspire guys to hopefully do big things and make it a real special thing -- if we can even close this team [the Giants] out. We haven't won anything yet and everyone knows that. We're not looking forward until we win one more game here. We have to put all of our cards on the table in terms of beating the Giants."
Bruce insisted the Cueto injury has not dampened the Reds' enthusiasm.
"Obviously, you feel better with your ace on the mound, but you know what? We're confident in every guy on the team," Bruce said. "Good teams find a way to win."
Adam McCalvy is a reporter for MLB.com. Read his blog, Brew Beat, and follow him on Twitter at @AdamMcCalvy. Mark Sheldon is a reporter for MLB.com. Read his blog, Mark My Word, and follow him on Twitter @m_sheldon. This story was not subject to the approval of Major League Baseball or its clubs.