The Astros placed Diaz (oblique) on the 10-day injured list Tuesday, Brian McTaggart of MLB.com reports.
A left oblique strain caused Diaz to be scratched from the lineup ahead of Monday's contest and will now also prevent him from playing for another 10 days. Christian Vazquez will presumably take over as the Astros' primary catcher while Diaz is on the shelf, and Nick Allen (back) will come off the injured list to claim the open roster spot.