Diaz (head) stepped in behind the plate to catch for Felipe Vazquez in the ninth inning of Tuesday's win over Washington.
He did not start after getting hit in the mask by a swing and leaving Monday's game, but the fact that Diaz was available to catch a day later means he passed tests for a concussion. The 28-year-old Diaz has underwhelmed with the bat after a strong 2018 season, and he's been downright bad since the break, posting a .456 OPS in 25 games.