Manager Craig Albernaz said that O'Neill is dealing with right shoulder soreness and is set to get an MRI Tuesday evening, Jacob Calvin Meyer of The Baltimore Sun reports.
O'Neill injured his right shoulder when he made a diving catch in Saturday's 3-2 win over the Rays. The right-handed batter would likely have started in Tuesday's contest against the Cardinals, who have southpaw Matthew Liberatore on the mound. Luis Vazquez is on the taxi squad in the scenario he is needed, Andy Kostka of TheBanner.com reports.