It's official - Melbourne have signed midfielder Harley Bennell for the 2020 season as a rookie.

The ex-Sun and Docker joins the Demons under the AFL's Supplemental Selection Period Rule.

The injury-prone onballer has not played at the top level since 2017, mainly due to ongoing calf issues.

The former pick No. 2 has played 83 AFL games, with just two of those appearances coming at Fremantle.

But the 27-year old has been thrown a lifeline by the Demons after impressing over the summer pre-season training.

“We are really pleased to welcome Harley to Melbourne through the SSP, and officially have him as part of our list for the 2020 season,” Melbourne general manager of football operations Josh Mahoney told the club website.

“Since joining us to train in December, Harley has shown nothing but commitment to his individualised program and to the club.

“Although he has faced some minor setbacks over the past two months, he has taken this opportunity with both hands, and maintained a strong, positive outlook.

“Harley’s positive attitude has seen him been embraced by the playing group and seen him develop close relationships in a short time.

“We’re excited to be able to reward him for his efforts so far and give him further opportunity to reach his full potential.”

Mahoney added that Bennell will be on a modified program as he builds up towards full match fitness, having suffered a minor calf setback last month.

“Harley’s journey will be long-term, and both he and the club are aligned in where he’s currently at in terms of making a return to playing,” he said.

“He understands the importance of undergoing a slow, modified program, and he knows there may be further challenges to tackle along the way.

“We think that by making this decision early, it will take away an undue pressure and enable Harley to concentrate fully on this program.

“We’re confident that he has the right attitude to embrace these hurdles, and we’re looking forward to working with him throughout.”