Diaz exited Tuesday's game against the White Sox with back spasms, Mike Wilner of Sportsnet 590 The Fan reports.
Diaz showed discomfort after hitting a single in the bottom of the sixth inning and did not retake the field in the seventh. The 27-year-old was 3-for-3 with a home run, a double and three RBI before leaving the game. Gift Ngoepe took over at shortstop for the Blue Jays, while Diaz should be considered day-to-day until he is evaluated further.