COLEMAN medallist Josh Kennedy cannot explain his wayward goalkicking in West Coast's Western Derby win on Saturday night but he plans to sharpen up this week against Richmond.

Kennedy inexplicably kicked 1.4 in the 33-point win over Fremantle. 

The Eagles kicked 12.20 on the night but Kennedy said the conditions weren't to blame despite some wind and rain in the second half.

Kennedy said he was at a loss to explain a couple of his misses from close range.

"I just couldn't do anything right on the night," Kennedy said on Monday. 

"But lucky enough it didn't really matter with the result in the end.

"I think with me, when I don't think about it too much and get too relaxed, that's where you make mistakes. I suppose you overcorrect sometimes and you start adjusting with the wind and aim for this and aim for that. But I kicked four points. Hopefully I'll kick a bit straighter this week."

It was a physical Derby and the Eagles had some sore bodies, including Kennedy who needed stitches above his right eye after being cut open during the game.

But he felt for Dockers big man Aaron Sandilands, who suffered a collapsed lung and several fractured ribs courtesy of a knee into his back from Nic Naitanui in a marking contest. Sandilands required surgery on Sunday and will spend a couple of days in hospital. No timeframe has been placed on his return but he is expected to spend a significant period on the sidelines.

Kennedy knows first-hand at least some of the discomfort Sandilands is enduring, having suffered a punctured lung of his own while playing in the VFL when he was on Carlton's list.

"I did it a few years ago and it's not very pretty especially when you're sitting in hospital trying to let it repair itself," Kennedy said.

"But it's a part of footy, I suppose, and there's always injuries that happen and that's not a very nice one, what Aaron had.

"All I remember is being in hospital for two or three days, which was the most annoying part.

"You can't really breathe too much. You're just short of breath. To be honest it just felt weird. It's not a very nice thing to happen." 

The Eagles have a second consecutive six-day break heading into Friday night's clash with Richmond at Domain Stadium. But Kennedy had confidence the players would recover well despite the short turnaround.