Nathan Lyon's durability will be needed more than ever this summer as Australia prepare to take on England with their spin cupboard looking bare outside of their star tweaker.
Australia's Plan A for the Magellan Ashes series will undoubtedly be for Lyon to play all five Tests while a second spinner may be called on if the SCG takes turn for the fifth Test.
But an untimely injury to Lyon in the next two weeks, as unlikely as that would be for a man who has never missed a Test due to injury, would leave the Aussies scrambling for a spin replacement.
The three other Australian spinners to have played Test cricket in the past five years, Steve O'Keefe, Ashton Agar and Jon Holland, are all currently sidelined due to injury and appear unlikely to play any first-class cricket before the Ashes begin later this month.
Holland, who is recovering from knee surgery, suffered a minor setback this week when his plan to play for Victoria's Toyota Futures League side was scuppered.
The left-armer, who played two Tests in Sri Lanka last year, is now in a battle to be fit for Victoria's final JLT Sheffield Shield game before the Ashes, starting on Monday against Tasmania.
Left-armer Agar, who impressed on the recent Test tour of Bangladesh, is expected to return to training on November 20 after he broke his finger on the recent ODI tour of India.
"Ashton is in the final stages of rehabilitation from surgery on in his right little finger. He is scheduled to return to full training in a next week at the eight week mark post-surgery," WACA Head Physiotherapist Nick Jones told cricket.com.au.
"Should Ashton’s finger cope with the demands of unrestricted training next week, then a return to play date will be mapped out."
And O'Keefe, who has played five Tests this year, is also out of action due to a finger injury and is aiming to return in round four of the Shield later this month, after the first Test gets underway.
In the unlikely event that Lyon is sidelined for the first Test, the Aussies may have to turn to uncapped leg-spinner Mitchell Swepson or forgotten leggie Fawad Ahmed to step into the breach. Swepson was a non-playing member on Test tours to India and Bangladesh earlier this year while Ahmed, who came close to a Test debut in 2015, has started the Shield season with nine wickets in two matches for Victoria.
Alternatively, selectors could opt for an all-out pace attack with off-spinning allrounder Glenn Maxwell to provide spin support in the middle order.
But those scenarios would appear unlikely given ironman Lyon's reputation and he's shaping as a key pillar of Australia's quest to win back the urn this summer.
The off-spinner has played 69 of 73 Tests since his debut in 2011 and hasn't missed a match since he was surprisingly dumped at the start of the 2013 Ashes series. His absence from a single JLT One-Day Cup match last month due to a sore shoulder was a rare occasion where his body has forced him to miss some cricket.
With 46 wickets at 22 already this year, Lyon will likely finish the Ashes within touching distance of becoming just the sixth Australian to take 300 Test wickets. Currently with 269 scalps from 69 Tests, he's just 23 away from surpassing Craig McDermott (291).
It's a remarkable turnaround for a man who 12 months ago was on the verge of being dropped as part of the player purge following Australia's shock series defeat to South Africa.
And with England set to field left-handers Alastair Cook, Mark Stoneman, Dawid Malan and Moeen Ali, and possibly star allrounder Ben Stokes and reserve batsman Gary Ballance, the off-spinner will be a crucial weapon for skipper Steve Smith in all five Tests.
2017-18 International Fixtures:
Magellan Ashes Series
First Test Gabba, November 23-27. Buy tickets
Second Test Adelaide Oval, December 2-6 (Day-Night). Buy tickets
Third Test WACA Ground, December 14-18. Buy tickets
Fourth Test MCG, December 26-30. Buy tickets
Fifth Test SCG, January 4-8 (Pink Test). Buy tickets
Gillette ODI Series v England
First ODI MCG, January 14. Buy tickets
Second ODI Gabba, January 19. Buy tickets
Third ODI SCG, January 21. Buy tickets
Fourth ODI Adelaide Oval, January 26. Buy tickets
Fifth ODI Perth TBC, January 28. Join the ACF
Prime Minister's XI
PM's XI v England Manuka Oval, February 2. Buy tickets
Gillette T20 INTL Series
First T20I Australia v NZ, SCG, February 3. Buy tickets
Second T20I – Australia v England, Blundstone Arena, February 7. Buy tickets
Third T20I – Australia v England, MCG, February 10. Buy tickets
Fourth T20I – NZ v England, Wellington, February 13
Fifth T20I – NZ v Australia, Eden Park, February 16
Sixth T20I – NZ v England, Seddon Park, February 18
Final – TBC, Eden Park, February 21