MELBOURNE, AUSTRALIA - APRIL 01: Jake Lever of the Demons continues his comeback from a knee reconstruction during a Melbourne Demons AFL training session at Gosch's Paddock on April 01, 2019 in Melbourne, Australia. (Photo by Michael Dodge/Getty Images)

Premiership Demons defender Jake Lever was sent home from training on Monday after fainting at Casey Fields as Melbourne players made their return to pre-season training.

Following their premiership celebrations at the MCG on Sunday, senior Demons players hit the track in preparation for their title defence in 2022.

Undergoing an intense running session held by newly-appointed high performance chief Selwyn Griffith, Melbourne players were tested under sweltering conditions in Casey, with Lever even requiring medical assistance.

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According to 25-year-old spent a lengthy period being aided by club medicos on the sidelines, with Lever responsive and eventually returning to his feet.

The All-Australian defender was then able to leave the ground before being sent home to rest following the incident.

The alarming scenes were brought to the attention of senior coach Simon Goodwin, with a club spokesperson stating Lever "went a bit too hard, too early".

The rest of the Demons squad continued their training under the hot conditions, with new recruit Luke Dunstan and Demons draftees among those taking part in the running and skill drills.

Melbourne will begin their 2022 campaign in a grand final rematch against the Western Bulldogs on Wednesday, March 16 - opening the new AFL season.