Australia faces a huge challenge before the Ashes even begin.

Captain Pat Cummins’ lower-back stress injury has ruled him out of the opening Test, with Steve Smith confirmed to captain in his absence.

That means the team is missing both its on-field leader and the bowler who usually sets the standard for accuracy, control and intensity.

That challenge deepened on Wednesday when star fast bowler Josh Hazlewood and Sean Abbott left a Sheffield Shield match with hamstring concerns.

Abbott was picked in the Ashes Test squad as backup fast bowler, and has now been ruled out, further challenging Australia’s bowling depth and team morale.

The injuries highlight one of modern cricket’s key debates: pick the best team every game, or strategically rest important players to minimise the chances of them breaking down?

What makes Cummins and Hazlewood so important?

Cummins has taken 309 Test wickets – eighth most by an Australian.

On average, he gives away only 22 runs for every wicket he takes. This is a measure called a bowling average.

Cummins’ average is better than teammates Mitchell Starc (average 27), Hazlewood (24) and Nathan Lyon (30). Against England, his average improves to around 21 runs per wicket and he has dismissed England’s best batter Joe Root 11 times.

Cummins also takes a wicket about every 46 deliveries – the lowest (best) of Australia’s top 40 Test wicket takers.

Hazlewood is normally the steady hand beside Cummins, a reliable fast bowler who builds pressure through accuracy and consistency.

Between them they’ve taken more than 600 Test wickets, setting the standard for control and discipline. If both are sidelined, Australia loses not just speed but the rhythm and stability that have anchored its attack for years.

Since becoming Test captain in late 2021, Cummins has led Australia to 20 wins in 33 matches, a win rate of more than 60% – an elite percentage.

It’s clear his influence goes beyond bowling. He is the team’s calm decision-maker and a respected leader whose voice carries weight on and off the field.

Replacing them will not be easy

Replacing Cummins means finding more than just another fast bowler. It also means finding a leader who can inspire under pressure.

Cummins has built a reputation for staying calm, listening to his players and making brave tactical calls.

His even temperament has also reshaped Australian cricket’s public image after several rocky years.

Stand-in skipper Smith has captaincy experience and a strong winning rate as captain at 51%.

However, even small shifts in leadership style can affect team rhythm.

Research on team performance shows when leaders change, communication patterns and trust often take time to rebuild.

What is a lumbar stress injury?

Cummins’ lumbar stress injury means tiny cracks have developed in the bones of his lower spine. These can appear when an athlete repeats the same powerful movement again and again without enough recovery.

Over time, the small cracks can worsen, leading to pain and stiffness. The injury is especially common among young fast bowlers but it can recur later in a career if workloads aren’t carefully managed.

Cummins has battled similar back injuries before, missing several years early in his career.

Many fast bowlers struggle with back injuries.

Hazlewood’s hamstring concern is also common among fast bowlers, although it appears he may still play in next week’s first Test.

Hazlewood has previously experienced a variety of Achilles, side and hamstring issues.

Fast bowling is one of the hardest actions in sport. Each delivery involves sprinting, landing on a braced front leg and twisting the hips and back at high speed.

Sports science research shows the force through the lower spine in that moment can exceed several times a bowler’s body weight.

The risks and rewards of rotation

Cummins’ and Hazlewood’s concerns reignite a long-running question in cricket: should teams rest their best players to protect them, or always play their strongest side?

This idea, known as rotation, has long been an unpopular policy in Australian Test cricket.

Arguments for rotation include reducing the risk of overload and injuries, improved player mental and physical wellbeing, better performance and possibly even longer careers.

Retired New Zealand fast bowler Shane Bond previously declared:

there is a danger of losing more fast bowlers from Test cricket unless boards and team management rest them.

Another key argument for rotation is increased opportunities for other players.

But critics – such as former Australian fast bowlers Brett Lee and Glenn McGrath and Cummins himself – believe the best team should always take the field.

Some players have also voiced concerns about losing their spot in the team if their replacement performs well.

Australia has favoured consistency rather than rotation for its premier fast bowlers in recent years. However, this may start to change as Cummins (32), Mitchell Starc (35) and Hazlewood (34) enter the final years of their careers.

Along with Nathan Lyon (38 on November 20) the “fab four” are one of the best bowling combinations in Test history, having claimed 1568 wickets between them since debuting in 2010/2011.

However, that durability is now being tested.

Cummins’ replacement Scott Boland has been outstanding in his limited opportunities but at 36 he is also not a long-term replacement.

Future planning

Australia has an extremely busy international schedule in the next 18 months, including playing the most Tests (22) of any country in the current World Test Championship. Ten of these are scheduled in a three-month window next summer (December 2026-March 2027).

With three leading fast bowlers now carrying injury concerns, Australia’s habit of rarely resting its quick bowlers is again under scrutiny.

This means Australians will likely have to adjust to seeing some new faces in their Test bowling attack.

This article is republished from The Conversation, a nonprofit, independent news organization bringing you facts and trustworthy analysis to help you make sense of our complex world. It was written by: Brendon Hyndman, Charles Sturt University; Simon Board, Charles Sturt University, and Vaughan Cruickshank, University of Tasmania

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The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.