Vin Diesel understands how franchise movies work. While his return revived the dying franchise, he also knows that it kickstarted his career. So why will he quit after 'Fast and Furious 7?'

It is as much a mystery as an uncertainty, but it is very evident that the confidence and swagger that he had after the success of "Fast and Furious 6" have diminished. Vin Diesel is as big a star as he's ever been, but the loss of Paul Walker may have deflated the franchise.

The report from Yahoo Movies UK:

"Vin Diesel and other members of the cast will likely find filming difficult without their long term friend and it may be that working on the franchise loses a bit of its excitement and fun... some may find it just too strange to continue the franchise, particularly considering the nature of Walker's untimely death."

The producers have found a solution for the movie, but what happens afterwards is a big question mark, especially with Diesel. This has less to do with Walker's death and more with the "Riddick" actor's career options.

One of the more intriguing prospects is a possible Marvel project that he himself teased:

Yahoo Movies UK continues: "Diesel may also be led astray by his upcoming projects. He is starring in Marvel's 'Guardians of the Galaxy' which is likely to be, like all of Marvel's other films, a huge success. Marvel don't make stand alone films and particularly with the kind of box office the likes of 'Iron Man' and 'The Avengers' make, 'Guardians of the Galaxy' will almost certainly have countless sequels in the future. Never one to let a character go to waste, Diesel will also probably resurrect Riddick again for another outing one day but before that he is dredging up the character Xander Cage from 'XXX' for a third entry in that franchise after the last one starred Ice Cube. Add to these a videogame adaptation of 'Kane and Lynch', and Diesel looks set to be very busy over the next few years."

While the idea of "countless sequels" may be a bit premature, there is also the notion that Diesel will have a different project with Marvel. One with more speaking lines.

"Fast and Furious 7" has a lot to offer. Jason Statham joins the franchise. James Wan of "Insidious" and "The Conjuring" fame steps aboard. The franchise will live on with or without Dominic Toretto or Brian O'Conner (Paul Walker) as long as there is a story to tell. We'll find out about that on April 10, 2015.