A side strain is threatening to stymie Josh Hazlewood's second consecutive summer with the quick now racing the clock to prove his fitness for the series against South Africa.
Michael Neser replaced Hazlewood in the XI to face West Indies in the final match of the two-Test series, with the 31-year-old said to be experiencing "general soreness" after the series opener.
But officials have since confirmed Hazlewood had in fact come down with a mild strain in his left side.
"I feel for Joshy, he's pretty understandably flat," Cummins told Channel 7 on Thursday.
"It's a low-level strain in his side.
"He was a little bit sore after the last Test match, had a bowl in the nets yesterday to prove his fitness and was a bit sorer than we'd all hoped."
Then-coach Justin Langer took a conservative approach to Hazlewood's fitness when he suffered a side strain last summer, playing him in only one of five Ashes Tests.
The injury and Andrew McDonald's decision to favour spin on the autumn tour of Pakistan meant Hazlewood had played only one Test in 12 months before the series against West Indies began.
At the toss on Thursday, replacement captain Steve Smith said Hazlewood was no guarantee of lining up in the first of three Tests against South Africa, which begins in Brisbane next Saturday.
"I'm not entirely sure (whether he will play)," Smith told Channel 7.
"I guess the medical staff will monitor him closely this week. Fingers crossed."
Whether or not he plays in Brisbane, Hazlewood's injury raises concerns over the management of Australia's fast bowlers at the beginning of a congested six months on the cricket calendar.
After the series against South Africa finishes on January 8, Australia will turn its attention to the tour of India in February and March before the Ashes begin in England in June.