It's a tough call for the selectors. A Pearce has been one of the best stories of the season, and I'd hate for him to be subjected to the random injurious flailings of NicNat and his less-talented thuggish teammate Lycett in the ruck. But if not Pearce rucking in spells, then who backs up Sandi?
The BOM has it being 29 and sunny on Sunday, so I'm not sure naming a back-up ruckman is the right call either, given West Coast probably has a slight running / pace advantage already.
I reckon Johnno, Cox and Kersten should all be in the mix, and the selectors should go with the guy with the meanest look in his eye during the week. They all seem like pretty decent guys, so that might be fruitless, in which case I'd select Johnno and hope to use him as a forward decoy/tagger on McGovern as much as possible, and backing up in the ruck.