ADELAIDE ruckman Reilly O'Brien wants to stay at the Crows, but admits he may have to look elsewhere if the club pursues Collingwood star Brodie Grundy.

O'Brien's management and the Crows have started talks about a contract extension for the 23-year-old, who has eclipsed Sam Jacobs as the club's first-choice ruckman.

The Crows have also signalled their interest in Grundy if the South Australian – who is a free agent at the end of 2020 – declares he wants to move home.

"If a player like that is on the market … they'd be silly not to do their due diligence," O'Brien said.

"Potentially, if he did come, it might (influence my decision).

"At this stage, I'm looking to commit here and play some good footy over the next couple of months."

O'Brien wasn't concerned about not having a contract for next season as he kept his focus on the field.

"There are no offers set in stone, but the conversation has definitely started," he said.

"I'm in no rush.

"I'm happy just playing and contributing to the team." - Reilly O'Brien

The No.9 pick in the 2014 NAB AFL Rookie Draft, O'Brien bided his time in the SANFL – apart from two senior games in 2016 – before getting an extended run in round three this year when the durable Jacobs was injured.

He's taken his opportunity with both hands, averaging 35.2 hitouts per game (fifth in the League) and 14.1 disposals, to stay ahead of 198-game veteran Jacobs.

But despite the competition between the pair, that hasn't stopped Jacobs from assisting his protégé.

"We've got a relationship and there's certainly no awkwardness there," O'Brien said.

"He gives me advice every week.

"He's come up against a lot of opponents I've come up against and knows little tricks against them that work and what doesn't work and their little tendencies."

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O'Brien admitted he struggled for motivation at times in the past two years when he was stuck in the reserves.

He contemplated giving away football so he could focus on studying to become a doctor.

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"I was a little bit frustrated playing in the SANFL and not getting a look-in, and feeling a bit like groundhog day each year, doing the same thing," O'Brien said.

"While I was playing reserves, I was thinking, "Is footy the way for me?'

"Not that I was considering doing that, but it crosses your mind and it would've been another tough year.

"It's been awesome to play and I'm really enjoying it."

O'Brien faces another huge challenge when he takes on Port Adelaide's Scott Lycett in Saturday's Showdown at Adelaide Oval.

The Crows are likely to welcome back Tom Lynch and Wayne Milera after both impressed at training on Wednesday, however midfielder Cam Ellis-Yolmen is likely to be sidelined for another week after failing to finish the session.

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"I don't think (Ellis-Yolmen) got through the whole session, so he's in doubt," O'Brien said.

"They looked good those two (Lynch and Milera), they were flying out there."