MELBOURNE star Clayton Oliver has not returned to pre-season training with his teammates and is instead taking extended leave as he deals with personal issues.

Four-time best-and-fairest winner Oliver has battled injuries and medical issues in recent months, and has faced questions over his off-field behaviour.

Oliver left Melbourne's December training camp in Lorne early to deal with medical issues, and when his teammates returned to training at Casey Fields on Thursday he did not join them.

"Clayton has personal issues that he has been dealing with," football boss Alan Richardson said in a statement. 

"Clayton has been working extremely closely with his personal medical team, and with the support of key club staff, in order to manage these challenges. 

"The club fully supports Clayton taking this important time out, which will allow him to focus on these challenges. Our primary focus is Clayton's overall wellbeing, and we will continue to support him through this period. 

"It's important for Clayton that we respect his privacy and his need for time and space."

Oliver's professionalism was repeatedly questioned in 2023 amid doubts over his future at Melbourne.

The triple All-Australian was restricted to 15 games last season because of a drawn-out hamstring injury but returned before finals, when the Demons made a second consecutive straight-sets exit.

Oliver was then a trade target for clubs, with Adelaide among the clubs interested, despite being under contract until 2030 after signing a massive seven-year extension.

Melbourne ultimately did not put him on the trade table.

Coach Simon Goodwin said in October he had never considered trading Oliver, but he and chief executive Gary Pert both made it clear the midfielder needed to adhere to the Demons' standards.

The Demons' culture has been under fire amid Oliver's troubles, plus utility Joel Smith's provisional suspension for recording a positive in-season drugs test to cocaine.

Oliver also said he did not want to leave the AFL club, where he was a star of its 2021 premiership, but had been prepared to leave if Melbourne no longer wanted him.

In an interview on October 31, the 26-year-old also committed to knuckling down and meeting Melbourne's standards.

Oliver was pulled over by police on November 16 and charged with driving with a suspended licence.

He has been unable to drive on medical grounds since he was hospitalised following a seizure on October 12, which he partially attributed to side effects of his ADHD medication.

Oliver is due to face court on February 6.