The three others contending teams play each other many more times over the remainder of the season:
Pirates and Cards = 13 games
Cards and Brewers = 12 games
Brewers and Pirates = 10 games
This means 35 games of automatic .500 ball averaged among all the current contenders. Best case scenario these teams split the various series and the Reds slowly catch up on the entire pack by playing anything over .500 ball. Worst case scenario is that one team takes the majority of the games and becomes the clear leader. But in that event, at least the Reds will only have one team to catch.
The Reds play each of these teams 3 more times.
Each team (Reds included) have 3 more games with the Phillies.
The bulk of the Reds games in Aug and Sept are against losing ballclubs.