Australia skipper Pat Cummins and Nathan Lyon were on Tuesday ruled out of the final two Ashes Tests against England with the veteran spinner facing surgery and an extended period on the sidelines.

Quick bowler Jhye Richardson and spinner Todd Murphy were named as cover in a 15-man squad for the fourth Test starting on Friday at the Melbourne Cricket Ground.

Australia have already retained the famous urn with eight-wicket wins in Perth and Brisbane and an 82-run victory in Adelaide.

Cummins “won’t play any part in the rest of the series”, coach Andrew McDonald told cricket.com.au.

He returned from a lower back injury to lead Australia to victory in Adelaide in his first Test since July, taking six wickets in the match.

“That was a discussion that we had a long time out around his return. Yeah, we were taking on some risk. We’ve now won the series, and that was the goal,” said McDonald.

Cummins will now target full fitness for the month-long Twenty20 World Cup in India and Sri Lanka, starting in early February.

“To position him for further risk and jeopardise him long term is not something that we want to do,” said McDonald.

“Pat’s really comfortable with that. If he had any setback in the build-in as well, we would have shut him down straight away.”

Steve Smith, who captained the team in Cummins’ absence during the first two Tests, will lead the side again in Melbourne after missing Adelaide with vertigo symptoms.

‘Amazing’ Starc

His return means there will be at least three changes.

Usman Khawaja replaced Smith at four in Adelaide scoring 82 and 40 and should he be retained then Josh Inglis is shaping as the fall guy.

Lyon, 38, damaged his right hamstring saving a boundary on day five in Adelaide fielding and hobbled off.

He claimed his 564th wicket in the match to move clear of fellow Australian great Glenn McGrath and into sixth on the all-time Test bowling list.

“Nathan Lyon will have surgery on a torn right hamstring which will sideline him for an extended period,” Cricket Australia said.

Lyon’s replacement, Murphy, is in line to play his first home Test.

His seven previous appearances for Australia all came overseas. His last was in Sri Lanka earlier this year.

Richardson was included after a four-year Test absence, during which he underwent three shoulder surgeries.

Scott Boland and Mitchell Starc are likely to lead the seam attack after recovering well from Adelaide, with Michael Neser, Brendan Doggett and Richardson battling to join them.

McDonald paid tribute to 35-year-old Starc, who has sent down close to 100 overs in the series so far and remains in good shape.

“Starc’s amazing. He’s pulled up fine,” McDonald said of the leading bowler in the series.

Starc has taken 22 wickets in the three Ashes Tests so far at an average of 17.04, including a career best innings return of 7-58 in Perth.

He has also contributed 150 valuable runs with the bat down the order.

“He keeps running in and presenting the pace that he does,” said McDonald.

“There’s a lot to be learned around preparing yourself and targeting the right matches at the right time.”

Australia squad: Steve Smith (capt), Scott Boland, Alex Carey, Brendan Doggett, Cameron Green, Travis Head, Josh Inglis, Usman Khawaja, Marnus Labuschagne, Todd Murphy, Michael Neser, Jhye Richardson, Mitchell Starc, Jake Weatherald, Beau Webster