The Evo 2022 fighting game tournament in Las Vegas is underway, which will feature high-profile fighting game tournaments as well as special announcements about upcoming games in the genre. One of the hottest new fighting games on the market is the crossover fighter MultiVersus, and so it's no surprise that it is included on the event. However, Evo tournament regulations prohibit participants from choosing two MultiVersus fighters or competing on one of the stages.
Characters that were added after the launch of the open beta are not permitted in the MultiVersus Evo 2022 rules, therefore LeBron James and the Iron Giant are not available to MultiVersus tournament participants.
One of the MultiVersus stages has also been banned for tournament matches, presumably due to the same reason LeBron James and the Iron Giant have been banned. The Cromulons stage, inspired by Rick and Morty, was added some time after the open beta went live. This is the most likely reason why tournament-goers may not select it at Evo.
After MultiVersus' official launch, future Evo events and other fighting game tournaments will take place, but certain characters might be banned from those events as well. For example, a Velma and Jake exploit has recently been discovered by the community, and so it makes sense for officials to establish where those two can't be on the same in any future 2v2 tournaments.
If other characters are released relatively soon before a tournament start, the promoters may decide to exclude him from the tournament because participants may not have had much of a chance to play as Morty and against him.
Morty will be presumably added to MultiVersus when it launches its Season 1, although it remains to be seen when it will be released. MultiVersus Season 1 is currently without a release date, with the open beta being extended forever.
MultiVersus is now available for PC, PS4, PS5, and Xbox Series X in an open beta.