Diaz went 2-for-5 with a solo home run in Thursday's 13-3 loss to the Royals.
Diaz is out of the lineup for Monday's game against the Rangers, Brian McTaggart of MLB.com reports.
Astros general manager Dana Brown confirmed in an interview with Randy McIlvoy of KPRC-TV on Thursday that Diaz "will be the main guy" next season at catcher.
Diaz is not in the lineup Wednesday for Game 4 of the ALDS against the Twins.
Diaz will start at designated hitter in Game 3 of the ALDS versus the Twins on Tuesday, Matt Kawahara of the Houston Chronicle reports.
Diaz is not in the lineup Sunday against the Royals.
Diaz is absent from the lineup Friday at Kansas City.
Diaz went 1-for-5 with a three-run home run and two runs scored Monday against the Rangers.
Diaz is out of the lineup for Sunday's game against the Yankees.
Diaz went 2-for-4 with a two-run home run in Saturday's 5-4 loss to the Yankees.