Former first-round draft pick Tom Doedee is poised to put his hand up as Jake Lever's replacement in the Adelaide backline.

Doedee – the 17th overall selection in the 2015 NAB AFL Draft – is one of several players who will get the opportunity to push for a regular spot in the Crows' defence.

The departure of 195cm Lever to Melbourne leaves a hole in the Crows' backline, with his intercept marking and ability to spoil extremely crucial to shutting down opposition forwards.

Doedee – at 189cm – is 6cm shorter, but the 20-year-old was the leading intercept marker in the SANFL this year and finished second in the Crows' state league best and fairest, just one vote behind champion midfielder Scott Thompson.

The experienced Kyle Cheney (28yo, 188cm) can play on tall and small forwards, while former cricketer Alex Keath (25yo, 198cm) showed surprising pace for a big man in his breakthrough season this year.

Fellow defender Jake Kelly said Doedee and Keath were going to do everything they could to force their way into the side.

"Tom Doedee and Alex Keath are two guys who are really going to have big pre-seasons and they're going to really challenge for that Jake Lever spot," Kelly said.

"Tom Doedee is a really special player.

"He's really good at being the third-man in and intercept marking, so he can definitely be one to replace Jake."

Kelly – at 189cm – established himself in the side this year with his tenacity and ability to shut down medium-sized forwards.

He wants to become better in the air to cover for Lever's loss.

"Jake Lever's obviously gone, that leaves a gap with that sort of player that can come third-man in, take those intercept marks and come in for spoils," Kelly said.

"That's an area I'm really going to focus on this pre-season.

"Not to replace Jake Lever in that sense because I've got my own strengths, but that's an area I want to improve on."

The Crows' first-to-fourth-year players returned to pre-season training on Monday afternoon, before they are joined by the senior players on December 4.

Wingman Paul Seedsman made an earlier than expected return with his younger teammates at Thebarton Oval.

Delisted midfielder Cam Ellis-Yolmen also trained, knowing the Crows have committed to selecting him in the NAB AFL Rookie Draft if he isn't taken by another club in the national draft.

"Cam was the one talking in front of the group," Kelly said.

"He was just talking about how we've got a lot of work to do in the next two weeks when the older guys come back.

"We just don't want to float in with the older boys, we want to go, we've done two weeks of work, we're raring to go, catch up with us.

"That should be the mindset."