But what might happen next has manager Dusty Baker making contingency plans.
The Reds have used the same five starters in the first 60 games of the season, one of just three teams to have used the same rotation to this point in the season.
Leake went home Tuesday as a virus was circulating in the Reds' clubhouse, and the right-hander has received IVs the past two days.
Leake said before Wednesday's 5-3 Reds win that he feels better and should be good to go Thursday, but the situation has left a veil of uncertainty over Cincinnati's pitching plans.
How does Baker plan to handle the situation if Leake can't go far in the game or can't go at all?
"A lot of that depends on tonight," Baker said before Wednesday's game with the Indians. "If [Mat] Latos goes deep tonight, then we could go bullpen or long man then a couple other guys.
"It depends on tonight and it depends on how Leake comes out of it tonight and into [Thursday]. He's going to feel a little weak and a little sore. It's a day game too, which doesn't help."
Baker was looking ahead to a possible Thursday dilemma even in Tuesday's game, he said.
"That's another reason we went deeper with Johnny [Cueto] [Tuesday] night, too," Baker said. "To anticipate that we might need the bullpen [Wednesday], and definitely [Thursday]."
Cueto pitched a complete game in a 7-1 victory over the Indians, throwing 122 pitches. Latos did his part on Wednesday, going seven innings in the Reds' 5-3 victory.
Leake is 2-5 with a 4.97 ERA in 11 starts and is coming off a solid outing on June 7 -- going seven innings and allowing seven hits and four earned runs in a 5-4 loss to the Pirates.
The Marlins and Mariners are the only other teams this season to use only five starting pitchers.
Leake, if he makes the start, will be opposed by Indians right-hander Josh Tomlin (3-3, 4.96 ERA), who will be making his ninth start of the season.
In his last outing on Friday, Tomlin scattered eight hits in seven innings, as the Indians beat the Cardinals, 6-2.
Tomlin was coming off his poorest outing this season, when he allowed five earned runs over six innings in a 7-4 loss to Minnesota on June 2.
"He was aggressive, attacking the zone early," Cleveland manager Manny Acta said. "He had a good curveball with depth and that helped him keep those guys off-balance."
Indians: Brantley extends streak
Center fielder Michael Brantley has hit safely in 20 straight games entering Thursday's series finale. Brantley kept his personal-best streak alive on Wednesday with a fourth-inning single off Latos.
Reds: Phillips on a hot streak
Brandon Phillips had three hits, including a home run, and drove in three runs on Wednesday to give him 16 RBIs in his last 16 games. Phillips has hit .325 in his last 34 games after being moved into the cleanup spot.
At least one home run has been hit in each of the last 58 games at Great American Ball Park, dating to a homerless game vs. the Giants on July 29, 2011. It is the longest active ballpark homer streak in the Major Leagues and the longest home run streak in Great American Ball Park history.
The Indians' Jose Lopez and Phillips homered in Wednesday's game.