Double-A Erie placed Miller on its 7-day injured list Sunday due to an unspecified issue.
Miller opened the season on Triple-A Toledo's IL while he was recovering from October labral repair surgeries on both of his hips, but he was activated and assigned to Erie earlier in the week after completing a six rehab appearances across stops with three of the Tigers' lower-level affiliates. He made his debut for Erie on Tuesday and struck out two over three scoreless frames, but Miller apparently succumbed to a new injury coming out of that appearance.