Alvarez (knee) is not in the lineup for Monday's game against the Mariners, Chandler Rome of The Athletic reports.
Alvarez departed Sunday's 9-8 loss to the Angels after banging his right knee on the ground while sliding. He had been set to undergo imaging on the knee Monday, and while the results of his tests have not yet been revealed, Alvarez will miss at least one start. Jon Singleton will serve as Houston's designated hitter Monday.