Some fans on Reddit noticed that goalkeepers had been introduced to the 'rondo' drills, a popular training game in which a circle of players keep the ball from two defenders by passing it between them.
New signing Marcelo Pitaluga, who joined from Brazilian outfit Fluminese earlier this month, was seen taking part alongside stars Trent Alexander-Arnold, Andy Robertson and Diogo Jota.
One fan commented: "Are keepers usually involved in rondos? It's the first time I can see one getting involved in one."
Another said: "Can someone clarify, is this the first time we see a keeper joining the rondo session?"
With goalkeepers being expected to play out from the back as part of the modern game, it seems logical to sharpen their one-touch passing and decision making under pressure by taking part in the drills.
A third comment read: "Think this will be the new normal, makes total sense to with how attackers now put pressure on keepers when they have the ball at there [sic] feet."
Adrian has also previously been noticed taking part in the drill, with usual first-choice goalkeeper Alisson Becker out of action with a shoulder injury.
However, the Brazil international is returning to training at Melwood ahead of his return to full fitness.
They will be without star defender Virgil van Dijk after he was ruled out for an extended period with a knee ligament injury, sustained during last weekend's Merseyside derby after he was caught heavily by Jordan Pickford.