Diaz was removed from Sunday's game against the Diamondbacks due to a left shoulder strain, Ryan Bass of Rays.tv reports.
The veteran slugger went 1-for-2 with an RBI and a run scored prior to departing the contest. Diaz should be considered day-to-day as he continues to be evaluated, and he'll have a team day off Monday to aid in his recovery ahead of Tuesday's series opener in Kansas City.