PROMISING Adelaide ruckman Reilly O'Brien has re-signed with the Crows until the end of 2019.

The 21-year-old put pen to paper on a two-year contract extension that will see him continue to learn from the club's first-choice big man, Sam Jacobs.

O'Brien played two games last year, including his AFL debut against the Brisbane Lions in round 20.

The Calder Cannons product joined the Crows in the 2014 NAB AFL Rookie Draft and was promoted to the senior list at the end of last year.

“We are thrilled to have Reilly re-sign with Adelaide,” Adelaide's head of football Brett Burton told the club's website.

“To see him progress initially from the rookie list to earning a senior debut last season is a credit to him and the club’s coaching staff.

“We love his competitive nature and his willingness to learn and we look forward to seeing him continue to develop over the next few years.”

Meanwhile, the Crows have two vacant spots on their senior list after placing midfielder Cam Ellis-Yolmen on the long-term injury list.

Ellis-Yolmen will miss the season with a serious knee injury after tearing his ACL in the JLT Community Series.

The Crows' rookie-listed players are Jonathon Beech, Hugh Greenwood, Paul Hunter, Alex Keath and Ben Jarman.