The Marlins placed Ruiz (oblique) on the 10-day injured list Wednesday.
Ruiz sustained a high-grade left oblique strain in Friday's Grapefruit League game against the Nationals and is facing a projected recovery timeline of 6-to-8 weeks. With Ruiz and Kyle Stowers (oblique) both shelved to start the season, the Marlins bolstered their outfield by signing Austin Slater to a one-year contract Tuesday.