Cincinnati leads the National League's Central Division by a half-game over St. Louis and will meet the Cardinals for three games at Great American Ball Park starting Monday night.
The Reds reassumed the lead in the division with two wins in three early-week games at Pittsburgh, including a 9-4 triumph Wednesday in which Paul Janish went 3-for-3 with four RBI and hit a three-run homer to highlight a six-run seventh inning.
Johnny Cueto (11-2) tossed six innings of one-run ball to win a seventh straight decision over Pittsburgh, scattering three hits and two walks to go with six strikeouts.
Meanwhile, the Cubs sit fifth in the six-team division, 13 1/2 games behind Cincinnati.
Chicago recorded a season-high in runs and totaled 16 hits - including a career-high four from rookie Starlin Castro. Soto finished 3-for-5 with five runs batted in, while Tyler Colvin added a solo homer.
For Chicago, lefty Tom Gorzelanny faces the Reds for the third time this season while still seeking an initial win.
The 28-year-old got a no-decision in a 3-1 Cubs loss on April 11 in Cincinnati, then took a 14-2 thrashing on May 8 in Ohio.
Combined, he allowed 13 hits and four runs in 12 1/3 innings.
Lifetime against the Reds, Gorzelanny is only 3-3 in eight starts, but he's been lights out against everyone else lately, winning four straight starts in July.
In fact, Gorzelanny's last loss was May 26 against the Los Angeles Dodgers. Since, he's 4-0 with a save and a hold in 12 games, which included a June stint in the bullpen.
The Cubs are 7-14 in games he's pitched.
For Cincinnati, veteran righty Bronson Arroyo goes for a second straight win in response to a brief two-game skid.
The Key West, Fla. native allowed four hits and two unearned runs in a 5-2 win over Atlanta on July 31, five days after dropping a 3-2 verdict at Milwaukee that had followed an 8-5 loss to Washington.
Overall, Arroyo is 6-3 in 11 starts away from home this season, including a 12-0 rout of the Cubs at Wrigley on July 2, when he allowed two hits in six scoreless innings.
The 33-year-old is 8-6 in 20 career games against Chicago.
He is three wins shy of 100 in a big-league career that began with the Pittsburgh Pirates in 2000.
Cincinnati has had its way with the Cubs this season, winning seven of the 10 matchups.