Harley Bennell has impressed at Melbourne's pre-season training. Picture: AFL Photos

THE LONG game with Harley Bennell is set to continue with the injury-prone Demon suffering yet another calf strain. 

FULL AFL INJURY LIST How many weeks will they miss?

The 27-year-old only last week made big inroads at training when he graduated to skills training with the main group after a cautiously monitored pre-season program.

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But Melbourne football manager Josh Mahoney confirmed on Wednesday morning the former Sun and Docker had broken down yet again.

"Harley pulled up sore following a training session on the weekend and scans have shown a low-grade strain in his calf," Mahoney told SEN's website.

WATCH The pledge Harley makes to Demons

"While disappointing to have this occur again, we deliberately set expectations on Harley conservatively, allowing for some setbacks."

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It was always understood Bennell wouldn't play until at least the middle of the season, given his extensive history of calf complaints that has involved two operations and an overseas consultation with soft tissue expert Dr Hans-Wilhelm Muller-Wolfhart. 

The Demons still signed him on a one-year rookie contract in the Pre-Season Supplemental Selection Period in February because of his undeniable potential. 

It's his second minor setback since he joined the Demons as a train-on player in January.

Meanwhile, half-back Christian Salem remains in the frame for round one despite a recent bout of glandular fever.

The 24-year-old didn't play against Hawthorn on Friday night but is starting to ramp things up as he emerges from the virus that can cause lengthy periods of fatigue. 

"Christian has a mild case of glandular fever," Mahoney said. 

"Pleasingly, he has been improving each day and completing running sessions and it still likely to be in the mix for round one."

Demons captain Max Gawn confirmed to AFL.com.au on Tuesday that forward Sam Weideman was also likely to be available for the season opener despite rolling his ankle against the Hawks.

The Demons meet West Coast at Optus Stadium on Sunday, March 22.