MELBOURNE forward Jay Kennedy-Harris' hopes of being selected in round one have been dashed after he suffered a broken arm at training on Friday.

Kennedy-Harris will miss up to two months of football after scans revealed a fractured forearm sustained in a tackling drill in the session at Casey Fields.

The injury is shocking luck for the 21-year-old who was seen as a real chance to be selected in the Demons' opening team against St Kilda.

"Jay was involved in a tackling contest during a drill and got a whack on the forearm and came up pretty sore," Demons elite performance manager Dave Misson told the club's website.

"He went in for scans and it showed that he had a break.

"He'll go in for surgery where he is likely to have a plate inserted and his recovery is probably six to eight weeks."

Kennedy-Harris did not manage a senior game in 2016 after injuring his hamstring on three separate occasions during last season.

The speedy forward had impressed the coaching staff with his application over the pre-season and was in the frame to play his first senior match since round 23, 2015.

Kennedy-Harris, selected at pick No.40 in the 2013 NAB AFL Draft, has played 22 games for the Demons since making his debut in round one, 2014.

Co-captain Jack Viney was spotted at scans on Friday but it is understood he was only in there for a precautionary check-up.

Forward Aaron vandenBerg also had scans on his foot after it flared up recently, although it is not believed the injury is too serious.

VandenBerg had surgery on his left ankle last September after being hampered by the nagging injury for the past 18 months.

With Kennedy-Harris sidelined, Jeff Garlett (hamstring) in doubt for the start of the season and Dean Kent (back) racing to prove his fitness, young draftee Dion Johnstone may come into the minds of the Melbourne match committee.

Johnstone, pick No.68 in last year's draft, has not taken a backward step over summer and has shown the coaching staff that he is tough and that he can pressure the opposition.

The 18-year-old small forward, who played in the Demons' last JLT Community Series game against Carlton, was nominated by co-captain Nathan Jones as his pre-season bolter at the club's season launch on Wednesday night.

The Demons face West Coast next Thursday night in their last pre-season hit-out before facing the Saints in round one at Etihad Stadium on March 25.