Los Angeles had won eight in a row before losing 6-5 on Wednesday.
Castilla’s home run was his 17th of the season and plated his team-high 77th RBI. The Rockies’ third baseman is third in the NL with 51 extra-base hits, behind St. Louis’ Albert Pujols and Philadelphia’s Jim Thome, who have 54.
Estes improved to 5-0 in nine starts this season against NL West teams. Three of those wins have come against the division-leading Dodgers, who returned from a six-game road trip to Arizona and Houston and lost for only the second time in 16 games.
Los Angeles is hoping Perez can earn his first win since June 16.
Perez returned to the Dodgers rotation on Saturday after missing several starts because of tendinitis in his left rotator cuff, an injury that landed him on the 15-day disabled list on June 26.
The 29-year-old southpaw allowed nine hits and four runs—one earned—over five innings in the Dodgers’ 7-6 win over Arizona on Saturday.
Perez has fared well against Colorado in his career, going 5-3 with a 3.36 ERA in 11 appearances, including 10 starts.