We already know Buizel is the one battling Lucario.
I mean until now, we know Buizel is the one taking it. We have no confirmation and I doubt we will have a title like this if another one will be the one to drop it in the same episode. Unless he loses it's safe to say Buizel is the one taking it.
It doesn't make sense to put a title saying Buizel vs. Lucario if another one will be the one to drop the monster.
If the writers stick with the game teams for the all future gyms then were looking at:
Maylene- Meditite Machoke Lucario
Wake- Gyarados Quagsire Floatzel
Fantina- Drifblim Gengar Mismagius
Byron- Bronzor Steelix Bastiodon
Candice- Snover Sneasel Medicham Abomasnow
Volkner- Raichu Ambipom Octillery Luxray
volkner:
ash: pikachu, grotle, gliscor, lucario, monferno, buizel(all 6 are the star of the battle..i think it will be 6 on 6..they will probably add magnezone to his team and a pikachu)