The Astros announced Julks' demotion Monday but did not disclose a corresponding roster move. The team has an off-day Monday and was in Washington visiting the White House in honor of winning the World Series last year.
Julks, 27, is batting .245 with six home runs, 35 runs, 32 RBIs and 15 stolen bases in 86 games in this, his rookie campaign. His playing time has diminished recently amid his struggles. The Astros selected Julks in the eighth round of the 2017 draft.
Astros general manager Dana Brown said Sunday the team is mulling whether to call up former top prospect Jon Singleton, 31.
The Astros open a series in Baltimore on Tuesday and are expected to announce a move earlier in the day.
Reuters contributed to this report.