That is possible. Kalos, so far, has been like a combination of Sinnoh and Hoenn. They share many similarities.
It is very very possible that Goodra could just be going into training, similar to Gliscor. If I am not mistaken, Gliscor was also afraid to battle or something similar. Goodra will be the first fully evolved Dragon pokemon Ash has, so it does make sense for him to let someone train it a bit better.
This would give Ash the ability to catch two more pokemon, explaining why Ash caught Hawlucha.
This would allow Ash to catch an Ice type in the snowy region and then allow him to catch a Phantump in the Haunted Forest before the League or before the 7th gym. Similar to how he did with Gible. And I can believe this a bit more than releasing Goodra. However, we do not know what the writers are thinking in this.
Another thing I have seen is this: Johto and Sinnoh, both even number gens. Has a pokemon leave Ash's team to train, but comes back later on. Charizard and Gliscor. So there is still hope that Goodra will stay with Ash, but just leaves to train.