O’Brien, 19, takes the place of draftee Harry Dear, who has been moved onto the long-term injury list as he recovers from a shoulder reconstruction.
A 201cm, 98kg, ruckman O’Brien was selected with the Club’s first pick (No.9) in last year’s AFL Rookie Draft. The competitive big man impressed in two NAB Challenge games against North Melbourne and Geelong, leading the ruck in the absence of Sam Jacobs in the clash with the Roos.
He’s played in all four of Adelaide’s SANFL games this season, averaging 13 possessions, 31 hit-outs and four tackles. O’Brien, who won eight clearances against South Adelaide last weekend, is ranked fourth in the League for hit-outs and also hit-outs to advantage.
The former Calder Cannon is the second rookie to earn an upgrade to Adelaide’s senior list this season. Defender Jake Kelly was promoted ahead of his AFL debut against Melbourne in Round Three.
A rookie must be promoted to the senior squad in order to be considered for AFL selection, including as an emergency.