Cueto will try to take over the major league lead with his 15th victory Friday night when the visiting Reds continue a four-game set against the Colorado Rockies.
Cincinnati (60-61) announced on Thursday that Homer Bailey, who was slated to start Saturday, is headed to the disabled list with a strained right elbow.
Fortunately for the Reds, they have Cueto (14-6, 2.05 ERA) taking the mound Friday. He is 6-0 with a 2.23 ERA in his last seven starts, matching the longest single-season winning streak of his career from April 30-June 12, 2010.
He'll be trying to win five straight starts for the first time since July 8-Aug. 2, 2012.
The right-hander allowed two runs over eight innings with nine strikeouts in Sunday's 7-2 win over Miami. He leads the NL with a 0.91 WHIP and is second to Washington's Stephen Strasburg in the league with 181 strikeouts.
Cueto is 2-2 with a 3.63 ERA in six starts against the Rockies, including 1-1 with a 4.20 ERA in three at Coors Field. He's had a difficult time against DJ LeMahieu, who is 5 for 8 against him.
Jay Bruce went 0 for 4 in a series-opening 7-3 loss Thursday as he returned to the lineup after missing a game with an illness.
He figures to face a difficult test Friday against Rockies starter Franklin Morales (5-6, 4.97) since Bruce is a .181 hitter against left-handed pitchers - one of baseball's worst marks.
Morales will start against the Reds for the first time after not allowing a run in 4 2-3 innings over five relief appearances against them between 2009-10.
He's 1-2 with a 3.31 ERA in six starts since re-joining the rotation July 3. That's a dramatic improvement from when he went 3-4 with a 6.13 ERA in 11 starts in the season's first two months before he was demoted to the bullpen.
Morales is limiting left-handed hitters to a .226 mark this year and .203 in his career. He has never faced the lefty-swinging batters the Reds used in their lineup Thursday in Bruce and Skip Schumaker.
The injury-plagued Rockies (47-74) have already lost star shortstop Troy Tulowitzki for the season and announced Thursday that injury-riddled outfielder Carlos Gonzalez was also out for the year.
Colorado won for the fourth time in its last 18 games Thursday behind Charlie Culberson, who hit a three-run homer. Culberson made his second straight start at shortstop.
''Not Tulowitzki,'' cautioned Culberson, ''but if they put (me) in the lineup, I'll be ready to play.''
Drew Stubbs went 2 for 4 with his first RBI against the team with which he began his career from 2009-12.
The Reds have dropped 12 of their last 16 road games and 15 of their last 20 in Denver.