Coming off consecutive complete games, Latos looks to help the visiting Reds prevent Volquez and the Padres from extending their season-high winning streak to six games Friday night in a matchup of pitchers traded for each other during the offseason.
In his first three major league seasons from 2009-11, Latos (7-2. 4.42 ERA) went 27-29 with a 3.37 ERA in 72 starts for San Diego.
He expected to remain with the Padres, but the Reds (44-37) were willing to pay a hefty price to acquire him. They dealt Volquez, former first-round picks Yonder Alonso and Yasmani Grandal and reliever Brad Boxberger to San Diego in December.
While Alonso and Grandal have become everyday players, Volquez (5-7, 3.68) has helped San Diego's rotation after struggling mightily last year, getting sent to the minors twice during his fourth season with Cincinnati.
"I'm excited," Volquez told the Padres' official website. "I look forward to pitching against them. It's going to be fun."
Latos, 7-0 with a 3.72 ERA in his last 13 starts after going 0-2 with an 8.22 ERA in his first three, faces his former club with a chance to become the first Reds pitcher since Jose Rijo in 1990 to throw three straight complete games in the same season.
He's allowed a run in each of his last two outings while yielding six hits and striking out 20 over that span. The right-hander gave up two hits and walked none during a 2-1 win at San Francisco on Saturday.
"When a guy gets a feeling and gets on a roll, let him roll and be as natural as possible," manager Dusty Baker told the Reds' official website.
Latos also has benefited from 5.90 runs of support per nine innings, which ranks among the highest in baseball. Volquez, meanwhile, has the majors' second-lowest run support average at 2.69.
The Padres, however, have scored more than enough while Volquez has yielded one earned run and seven hits in 12 2-3 innings to win his last two starts. The right-hander overcame a season-high six walks - his ninth time this year walking at least four - to beat Colorado 8-4 on Saturday.
Volquez, who leads the majors with 60 walks, hopes his teammates can continue to swing the bats well after scoring 33 runs during their five-game winning streak. San Diego (33-50) has not won six in a row since an eight-game run April 16-24, 2010.
Alonso had two hits with two RBIs and Grandal broke a tie with a pinch-hit homer in the eighth inning Wednesday as the Padres completed a three-game road sweep of Arizona with an 8-6 win.
Grandal is 6 for 19 with four home runs in five games since being recalled from the minors Saturday.
"You need to make a statement when you come into the league," Grandal said, "and I guess it's working."
The Reds have scored one run in each of their last two contests, losing both to fall one game behind first-place Pittsburgh in the NL Central. Devin Mesoraco homered for one of Cincinnati's three hits in Wednesday's 4-1 loss at Los Angeles.
Reds star Joey Votto is 3 for 8 since missing two games with knee inflammation. He's batting .400 (16 for 40) with four homers and 11 RBIs in 12 games at Petco Park.