Perth's undefeated BBL title defence will continue without star pacemen Nathan Coulter-Nile and Jason Behrendorff for the rest of the season.
The pair, who've both represented Australia in limited overs cricket, have failed to overcome back injuries.
Coulter-Nile endured a recurrence of a stress fracture soon after playing for a Western Australia XI against England in November.
The injury also rules the 30-year-old out of January's one-day international series against England.
"He is still experiencing pain and will need a longer recovery period so will not be available," Cricket Australia chief medico Alex Kountouris said on Wednesday.
Left-armer Behrendorff last played in a Sheffield Shield game in late November and has since succumbed to lower back pain, an issue he previously had been managing.
"Despite not bowling since this flare up, his pain has not settled sufficiently to be able to return to bowling," WACA head physiotherapist Nick Jones said.
"Jason requires an extended period of rest from bowling to allow this pain to resolve and will not be available for the remainder of BBL07 and the T20 series against England and New Zealand later in the summer."
Despite their absences, the Scorchers are 4-0 thanks largely to paceman Andrew Tye's 13 wickets.
