The media are permitted to capture the first 15 minutes of the squad's preparations prior to each UEFA Champions League game.
Victor Lindelof was back after injury for the Reds, ahead of Tuesday's all-important Group A fixture against Bayern Munich, but Anthony Martial and Marcus Rashford were missing through illness.
Martinez was briefly seen with the group as they emerged out on to the pitches, before going off to conduct some individual work as part of his injury rehabilitation.
The Argentina international has been out of action for almost three months, with the reverse fixture, in Munich, marking his most recent Reds appearance.