ADAM Simpson rates Shannon Hurn as the smartest player on West Coast's list, and believes the long-kicking defender's attention to detail will make him an ideal leader as he prepares to captain the Eagles for the first time.

Hurn will get his opportunity to skipper his side against Fremantle on Saturday as part of West Coast's ongoing search to find a long-term replacement for Darren Glass.

Josh Kennedy and Matt Priddis have led the side in the first two matches since Glass retired, and both rose to the occasion in victories. 

Kennedy bagged seven goals against Gold Coast, while Priddis collected 30 possessions and kicked a goal last Sunday against St Kilda. 

Simpson believes Hurn would step up just as well with the extra responsibility. 

"He's actually probably our smartest - in terms of football smarts - player at the club," Simpson said. 

"He knows the game. He loves the game. He's not one of those players who switches off in terms of going home and not watching a game. 

"He's up to speed with what's going on in football. He's vocal and demanding, all the things you look for in a leader."

Aside from rotating the stand-in captaincy role since Glass stepped aside, Simpson has also rotated West Coast's substitute in his first year at the helm. 

The Eagles have had 10 different substitutes this season, with Dom Sheed (three times) and Will Schofield (twice) the only players to have worn the green vest on more than one occasion.

The coach has wrestled with how to best use the sub, but believes substitutes haven't been as damaging across the competition as previous years. 

"You used to see a sub come on and have real impact," Simpson said. 

"Sure, there's certain times when players have stood up. But it feels like the role is changing a little bit. So we're working through that. 

"We haven't got a consistent sub that we go with.
   
"We've probably got five or six players who are playing at a level that we would like to see more out of, but they're not playing to a point where they need to be dropped. Sometimes it's part of that."

Simpson was unsure whether the new rotation cap had anything to do with his thoughts on the substitute, or whether his team simply had not got the impact from the sub he was searching for.

"I don't know if it's the rotations or the game, the way it's played at the moment," Simpson said. 

"It just feels like we're not seeing that spark when they come on. Maybe it's just us."