Are executives at 21st Century Fox (NASDAQ:FOXA) afraid audiences will forget about its Marvel properties? It sure looks like it, Fool contributor Tim Beyers says in the following video.

How so? Shortly after Walt Disney (NYSE:DIS) and Marvel released a new trailer for Captain America: The Winter Soldier, Fox responded with six seconds of teaser footage of X-Men: Days of Future Past, which is due in May 2014. The studio has since released a full trailer.

There's a lot riding on Days of Future Past, Tim says. The seventh installment in Fox's series of X-films, Days bridges the events of the last team film -- the largely unsuccessful X-Men: First Class -- and this summer's The Wolverine, a lower-budget epic that earned a respectable $405.6 million worldwide. Days could put up similar numbers if word of mouth builds ahead of release. Strong buzz for Captain America, which releases a month earlier, could get in the way.

Should Fox investors temper expectations? Or will X-Men: Days of Future Past kick off a string of new mutant-themed Marvel films from the studio? Tim addresses these questions in the video. Please watch now, and then leave a comment to let us know what you think.