Rainey (collarbone) is scheduled to pitch during Sunday's Grapefruit League game against the Mets, Jesse Dougherty of The Washington Post reports.
The 28-year-old has yet to see game action in spring training due to a minor muscle strain near his right collarbone, but he's set to take the mound during Sunday's contest. Rainey completed a couple simulated games throughout the past week, and he should have enough time to get fully ramped up for Opening Day.