Diaz (foot) will be the designated hitter Wednesday and will start at catcher in Friday's Grapefruit League game, Matt Kawahara of the Houston Chronicle reports.
Diaz was delayed due to a foot sprain suffered in the Dominican Winter League, but he isn't too far behind, as he's scheduled to catch in a game before the end of February. Cesar Salazar is Diaz's only backup, so there should be ample playing time available for the latter once he puts the foot sprain behind him.