He has returned.
To my recolection, Sinnoh's the only region where there wasn't a 2 on 2 gym formatAlso, poor Marlon was beaten quite too fast unlike Roxie, not to mention a damned 2-on-2 is completely unheard of in this anime.
Previous two vs two matches.
Kanto:Brock, Misty, Koga
Jouto: Chuck, Jasmine, Pryce
Hoenn: Roxanne, Brawly, Liza and Tate