PECOTA is not friends with the Astros. In the article "Resetting the Playoff Races" on Baseball Prospectus Daily, they take aim at the playoffs, and briefly, the Astros.
The Astros can be found under "Teams whose playoff odds are similar to what they were at the beginning of the season," subtitled with the Pirates, Padres, Orioles as "clubs who lacked more than an ice cube's chance in hell to begin with."
Currently BP gives the Astros a 4.5% chance of winning the NL Central, and a 0.7% chance of the Wild Card. That 5.2% playoff chance is 1.9% higher than what the Astros were given at the beginning of the season. Never mind the fact that PECOTA also projected the Astros to go 66-96, 29 games behind the Cubs. Look at the standings, and...yep, the Astros and Cubs are right there together. Never mind that the Astros need to go 22-52 to close the season and finish where BP projected (that's a winning percentage of .297. Even the Nationals went .299 in the first half...)