ST KILDA'S Ben Long is bracing for a stint on the sidelines after being reported for a high bump that left Fremantle's Sean Darcy concussed on Saturday. 

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Darcy failed to return after being flattened by Long in the second quarter, when the St Kilda defender opted to bump and brace for contact rather than attempt to pick up the loose ball. 

>>WATCH the incident in the player above

It left the Dockers reduced to two rotations after half-time in their stunning come-from-behind win after earlier losing Hayden Young to an ankle injury that will require scans. 

Should the Match Review Officer grade Long's bump as high impact – given Darcy missed the rest of the game – he will receive three weeks if it's deemed intentional conduct or two weeks for careless conduct.  

Dockers coach Justin Longmuir said his No.1 ruckman was in good spirits after the six-point win but was unsure if the incident had knocked him out. 

"He was rattled and the docs wouldn't allow him to go back on so make of that what you want to make of it," Longmuir said.

"He seemed fine in the rooms just then, he's not dazed or anything like that so if he was knocked out, he's recovered really well."

Darcy's injury prompted the Dockers to move Rory Lobb into the ruck after half-time, with skipper Nat Fyfe shifted forward to provide a target.