Hazlewood missed the ongoing day-night Test against the West Indies at Adelaide Oval due to a low-grade side strain. He will be travelling to Sydney on Friday for rehabilitation and will be assessed after the West Indies series.
"I feel for Joshy, he's pretty understandably flat," Cummins told Channel 7.
"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."
Hazlewood has played only two test matches in the last 12 months, with his latest outing being the Perth Test against the West Indies. He featured in the Australia XI once during the test series against Pakistan and Sri Lanka.
There have been a lot of questions arising on the fact that Australia has lost two of their premium bowlers with injuries at the start of the season. The fast bowlers have been through a grind for the last three months as they played continuous cricket, including ODIs and T20 World Cup.
"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."
Micheal Neser and uncapped WA quick Lance Morris were called in before the second test against West Indies. In the second test, Scott Boland and Neser replaced Cummins and Hazlewood in the playing XI.
Mitchell Starc has pulled up really well in tests with his outstanding resilience. Starc played all 10 tests against England, Pakistan and Sri Lanka, claiming 22 wickets in 15 innings this year with an impressive economy of 3.08.