Johnson is due to fly out to South Africa on Friday ahead of Australia\'s Test and one-day tour.
Melbourne: Australia's bowling spearhead Mitchell Johnson injured his left ankle on the opening day of Western Australia's Sheffield Shield clash with Tasmania at the WACA Ground on Tuesday.
Johnson grimaced after his back foot slipped as he came in to bowl the fifth ball of his second spell.
The 29-year-old looked uncomfortable before he rose to his feet and left for treatment.
Western Australia's medical staff confirmed Johnson had rolled his ankle and would be further assessed on Wednesday morning to determine whether he could bowl again in the match, The Australian reported.
Johnson is due to fly out to South Africa on Friday ahead of Australia's Test and one-day tour against the Proteas.