Carlton key forward Harry McKay and West Coast's Brad Sheppard have both suffered concussions in their sides' AFL clash at the SCG.
Substitutes Jamaine Jones and Jack Newnes were both called into the fray during Sunday's second term.
The Eagles, already minus captain Luke Shuey and a stack of key players, were forced to substitute Sheppard after his accidental clash of heads with Adam Saad.
Sheppard was floored after attempting to tackle Saad in the first quarter.
McKay's head knock came in a separate incident during the opening term, when the Coleman medal leader's head slapped the ground after flying for a mark.
West Coast held an eight-point lead at halftime of Sunday's match.
