MELBOURNE has defended its handling of Jack Watts after the forward was again left out of the club's JLT Community Series clash.

The Demons will play against Carlton at Casey Fields this Saturday with Watts and speedster Jeff Garlett the notable omissions.

Garlett will miss because of a hamstring injury but the reasons behind Watts' non-selection are still unclear. 

Melbourne football manager Josh Mahoney said Watts understood what was required of him to return to the senior team, repeating Tom McDonald's assertion from Tuesday.

"We think there has been some predictable, but unfair media speculation about Jack Watts' non-selection. To clarify, the team is being selected on some key criteria during the pre-season," Mahoney said. 

"Jack knows exactly what needs to be worked on, and his past two or three weeks he's been working hard on what he needs to improve on in certain areas.

"He still remains a key player for us this season."

Desperate to be recalled for Saturday's game against Carlton, Watts was vocal throughout Melbourne's almost two-hour training session at Gosch's Paddock on Thursday morning. 

During an 11-versus-11 match simulation drill, Watts earned praise from coach Simon Goodwin for his defensive positioning. 

Watts' ball use was clean but his intensity – particularly when in transition during a full-ground match practice drill – appeared to be a little lacking. 

He also seemed to have his right thumb heavily taped and there have been suggestions he is nursing a hand issue. 

After training, Watts worked on his contested marking against Cam Pedersen as coach Goodwin kicked footballs between them.

Garlett is in danger of missing round one and is expected to be sidelined for up to a month with his hamstring injury.

He ran laps and completed a boxing session at Melbourne training on Thursday, will be racing the clock to be fit for round one after scans showed a hamstring strain would keep him out for 3-4 weeks. 

Jack Watts soars in front of coach Simon Goodwin at Melbourne training on Tuesday. Picture: Getty Images

With Garlett on the injury list, it now opens the door for youngster Dion Johnstone, who has been selected for the game against the Blues, to push his claims for a round one berth.

Johnstone, pick No.64 in last year's NAB AFL Draft, has won admirers this pre-season for his defensive pressure inside 50 and for his aggressive attack on the footy.

Early in the training session, small forward Ben Kennedy appeared to hurt his right foot in a running drill in the warm-up.

The 22-year-old had the foot examined by the club's medical staff and took no further part in the session. 

The injury does not seem to be too serious and Kennedy was moving reasonably well when he was spotted back at the club after training. 

Star forward Jesse Hogan received treatment on his left hip flexor on numerous occasions but finished the session. 

Hogan often has work done on his lower back and hips during training as part of ongoing management of his body. 

In positive news for Melbourne, Dom Tyson (knee) and Dean Kent (back) are in full training and will push for selection in the Demons' last JLT Community Series game against West Coast.