Montgomery is out of the lineup for Sunday's game against the Astros after fouling a pitch off his right shin late in Saturday's contest.
The 24-year-old sat out of Tuesday's starting nine after fouling a pitch off the same shin Monday, and manager Will Venable said that Saturday's incident occurred just above the previous one, per Scott Merkin of MLB.com. Montgomery was able to finish his plate appearance Saturday but will miss at least one start due to the injury, but he's expected to return to action Monday versus the Yankees, per Merkin. Luisangel Acuna is working at shortstop in the series finale for Chicago.