Jones, 35, has been the favourite for the role since leading Wales to the Six Nations title in March.
The game’s most capped player with 157 Test appearances will pip closest rival Maro Itoje after leading Wales to success in the recent Six Nations, although there have been other contenders including Scotland star Stuart Hogg.
It would be 35-year-old Wyn Jones’ fourth tour, although his role as skipper in the squad announced by Warren Gatland would not guarantee him a place in the Test team.
However Jones' form in the Six Nations, as well as his aura, experience and remarkable longevity have convinced Gatland he is the man to succeed the retired Sam Warburton.
Jones has featured in the last nine Lions Test matches, including captaining the team to victory in the decisive third Test against Australia in Sydney in 2013.
Gatland will name a group of 36 – 20 forwards and 16 backs – at an announcement that is being streamed live online with players discovering for the first time if they have been selected.
One of the biggest calls facing Gatland is whether to include Manu Tuilagi, whose comeback from an Achilles injury in time for the final phase of Sale’s title push is imminent.
The powerful England centre has not played since September, ruling him out of the autumn and Six Nations and making his inclusion a risk, but Gatland will be aware of his unique ability to break the gainline and may decide he is worth the gamble.
The loss of George North to a knee injury has thinned Gatland’s midfield options and Tuilagi would potentially be a more explosive alternative.
Ireland captain Johnny Sexton could be one of the biggest casualties due to his ongoing issues with concussion that have limited his game time since the Six Nations.
His absence would open up a vacancy at fly-half, possibly for Finn Russell of Scotland with Wales’ Dan Biggar expected to tour and Owen Farrell likely to travel as a centre.
Marcus Smith has been shredding defences for Harlequins this season and the uncapped 22-year-old is among an extended group of over 50 players to have been notified that they are under consideration.
It would be a seismic call for Smith to be included among the 36, however, given he has yet to make his England debut.
Harlequins’ mid-season resurgence has propelled Danny Care into contention at scrum-half three years after the 34-year-old veteran of 84 caps fell out of favour under Eddie Jones, and hasn’t played for England since 2018.
Care has formed the Gallagher Premiership’s most creative half-back partnership alongside Smith and he could profit from Ben Youngs ruling himself out of consideration.