Diaz went 1-for-3 with a double against the Dodgers on Saturday.
He figures to see the bulk of playing time behind the plate for as long as starter Francisco Cervelli misses time with a concussion. Diaz is hitting .387 in his last 31 at-bats after shaking off a slow start. The catcher hit .286 with 10 homers and 34 RBI in 82 games for the Pirates in 2018.