Promoted rookie Reilly O’Brien will make his AFL debut against the Brisbane Lions on Saturday night.

O’Brien, 20, replaces experienced ruckman Sam Jacobs, who will miss his first game since 2012 because of an ankle injury.

O’Brien has established himself as one of the premier ruckmen in the SANFL since being recruited by Adelaide with pick No.9 in the Rookie Draft of December, 2014.

The 201cm, 100kg, competitor finished runner-up in the Club’s State League best and fairest award last year and has played every game this season. He’s averaging 25 hit-outs, 14 possessions and four marks per game in 2016, and has also kicked 10 goals.

A skilled tap ruckman, O’Brien ranks fourth in the SANFL for hit-outs to advantage (123). His aggression and follow-up work around the contest is also a strength.

O’Brien had a taste of AFL football in his first pre-season at West Lakes, impressing in two NAB Challenge games in 2015. The former Calder Cannon also lined up against Fremantle in Albany in February this year.

O’Brien was on the verge of an AFL debut last season. He was elevated to Adelaide’s senior list twice and named as an emergency on multiple occasions.

He was added to the Club’s primary list again last month under the AFL’s mid-season rookie rules.

He’s the third Adelaide player to debut this season following draftee Wayne Milera Junior and O’Brien’s housemate Mitch McGovern. Wingman Paul Seedsman also made his Crows debut in Round One.

Jacobs’ injury brings to an end the second-longest active streak of consecutive games (93) in the AFL.

At a press conference on Wednesday afternoon, Crows coach Don Pyke also revealed that 300-gamer Scott Thompson would miss the clash with the Lions as part of his ongoing management.

Captain Taylor Walker, who missed the win over Essendon with a sore ankle, will aim to prove his fitness at the Club’s main training session on Wednesday night.

Thompson’s replacement will be decided by Adelaide’s match committee, and announced when the team is released on afc.com.au at 5:55pm (local time) on Thursday.