Port Adelaide's Willie Rioli was subbed out at quarter time of Saturday's clash with North Melbourne due to a calf injury.
The club confirmed the change after the opening break, revealing Rioli sustained a strain to his calf in the first term and would not return to the match.
The Power small forward was pictured in the rooms while defender Lachie Jones was brought into the game and utilised forward.
The setback came amid early frustrations for Rioli, who did not record a disposal prior to quarter time.
Port Adelaide had two further injury concerns in the opening half, with Todd Marshall undergoing a concussion test in the second quarter before being cleared to return.
Midfielder Connor Rozee suffered a suspected ankle complaint early into the game at Blundstone Arena but was also able to continue.
North Melbourne are yet to require their tactical sub, with Charlie Lazzaro on standby.
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