ADELAIDE, AUSTRALIA - DECEMBER 05: Alastair Cook of England looks dejected after being dismissed by Nathan Lyon of Australia during day four of the Second Test match during the 2017/18 Ashes Series between Australia and England at Adelaide Oval on December 5, 2017 in Adelaide, Australia. (Photo by Ryan Pierse/Getty Images)

Timing is everything in cricket and nowhere has that been more apparent than with ex-England captain Alastair Cook calling time on his international career.

Assured a place among the all-time great Test runscorers, Cook was the last of a dying breed – an opening batsman with discipline and mental toughness to graft at the crease and put on a big score.

His announcement to step away from the international game with a series victory assured over India leaves England with about 11 months and two sets of away Tests over the winter to find a replacement.

Trevor Bayliss needs someone to stake their claims to succeeding Cook as the anchorman of the opening partnership either in Sri Lanka or the West Indies come the New Year, because – a single Test against Ireland apart – the next assignment in this form of cricket is a home Ashes series against Australia.

The touring Aussies are now made odds-on 10/11 favourites in bet365’s cricket betting to beat England in their own backyard next summer, with the hosts 13/8 to regain the iconic urn.

Losing someone with 12,000 odd Test runs to his name like Cook is an obvious blow. England have had to replace great players before, however, but there is a sense of a changing of the guard here.

Cook was a throwback. Some might call him conservative, but he truly was the last from an era when cricketers weren’t brought up to Twenty20s.

Shorter forms of the game are high on excitement, but often low on batting discipline. Playing rash shots at the crease with five days and two innings to get through is more punishing to a team’s chances by contrast.

To his credit, Cook has had the foresight to retire from the international game and give those who will try and fill his considerable boots the best part of a year to bed-in to the England set-up.

With Sri Lanka and the Windies both languishing in the bottom half of the ICC Test Rankings, Bayliss and captain Joe Root could hardly have better opposition against which to experiment.

Trial and error, as England have already found with their openers of late, is still a risky business, however. Lose either series and there will be bad press at home.

Not so long ago, it was Australia making headlines for all the wrong reasons. Their disgraced stars Steve Smith and David Warner could well be back to boost their bid to keep The Ashes as both batsmen’s bans expire before the series.

There is still the manner of how to go about replacing Cook to be worked out. He was thrust into the Test spotlight at the tender age of 21 and flourished, but others that have come along since seem to have wilted.

A left-field choice looks unlikely as the ECB’s selectors have afforded opportunities to a few players as partners for Cook in recent times. Finding the right combination, so they can still be a force is now the challenge, but time is on their side.