Diaz (hand) will start at designated hitter and bat leadoff in Friday's Grapefruit League tilt versus the Red Sox, Marc Topkin of the Tampa Bay Times reports.
Diaz missed more than a week of action while nursing a sore left hand, but he upped his workouts in recent days to clear the way for his return to action. The 34-year-old is slated to serve as the Rays' primary DH this season and will also see some playing time at first base.