Details of his ailment weren't revealed.
Smith posted a .902 save percentage and 2.95 goals-against average in 39 games with the Oilers last season. The 38-year-old veteran re-signed with the club on a one-year, $1.5-million contract in the offseason and was projected to serve as Mikko Koskinen's backup.
The Oilers recalled Stuart Skinner, who has no NHL experience, on an emergency basis. The 2017 third-round pick registered an .892 save percentage in 41 AHL games last season.
Additionally, the team reassigned Olivier Rodrigue, a 2018 second-round pick, from the Austrian League to the club's taxi squad, pending quarantine protocols. The 20-year-old owned a .908 save percentage in 23 games overseas.
The Oilers could also look to add a backup with NHL experience while Smith is sidelined.