Latino Review has reported rumor that Disney will begin introducing second-tier characters via short films, not unlike the short films released by Pixar, which preface their full-length features.
Got a scoop from a well trusted source that Marvel/Disney are looking at doing 10 minute short films in front of their feature length movies that will introduce secondary characters like Black Panther, Luke Cage, Dr. Strange, etc.
While it was previously reported that Disney was considering producing shorter films in the $20-40million range to introduce lesser-known characters to fans, this new mode would allow the same for a much smaller financial risk.