The Reds will take on Blackpool in a friendly at Anfield on Saturday, a week before Leeds arrive on Merseyside to kick off the league campaign.
As champions of England, they will be looking to get off to a strong start, but this has been dealt a blow by the timing of the international break, with 11 first-team players currently on duty.
However, as Klopp led a session at Melwood on Thursday, the return of Matip and Henderson was a big boost for Liverpool as they prepare for an important week.
Henderson has been sidelined since July with an ankle problem, while Matip has missed the last two months with a foot injury that saw him sit out of the final games of 2019/20.
Origi, meanwhile, has missed most of pre-season due to a minor injury picked up while at the Reds’ training camp in Austria.
The forward was selected for the Belgium squad, but appears to have now pulled out of their UEFA Nations League clashes with Denmark and Iceland to continue work with Liverpool.
Klopp was pictured working closely with 17-year-old centre-back Billy Koumetio, while Nat Phillips, Ki-Jana Hoever and Sepp van den Berg were also involved, giving the manager a handful of options at the back this weekend.
Matip could partner Phillips in defence, with Hoever at right-back and James Milner the likely candidate at left-back.
Fabinho and Naby Keita could be Henderson’s support in midfield, with a strong bank of quality in both the middle of the park and in attack, due to Africa, Asia and South America all postponing internationals.
The manager could also opt for a 4-2-3-1 formation, as seen in the final half-hour of the Community Shield last weekend, which would provide Takumi Minamino with an avenue into the side.
Blackpool visit Anfield for a 3pm kickoff on Saturday, with Neil Critchley in charge of the opposition after vacating his role as Liverpool under-23s manager in March.
The friendly provides the likes of Matip, Henderson and Origi with a chance to work towards match fitness, having missed the clashes with Stuttgart, Salzburg and Arsenal so far this summer.