Yamamoto was placed on the 10-day injured list Wednesday with a right forearm strain, Andre Fernandez of The Athletic reports.
This move comes after Yamamoto was tagged for six runs across 3.2 innings in his most recent outing -- easily his worst start since joining the Marlins in mid-June. Depending on the severity of the issue, the 23-year-old rookie may not pitch again this season; the Marlins are well out of playoff contention and have little reason to push Yamamoto, who is already approaching a career-high in innings. Robert Dugger was summoned from Triple-A New Orleans in a corresponding move and will replace Yamamoto in the rotation, starting Thursday against the Reds.