Ruiz was diagnosed with a left oblique strain following his exit from Friday's Grapefruit League game against the Nationals, Stephen Strom of Marlins Radio Network reports.
The initial diagnosis for Ruiz was left side tightness, but further tests revealed a more significant injury. Per Christina De Nicola of MLB.com, Ruiz will undergo further tests to determine the severity of the strain and whether he will need to open the season on the injured list.