Barry Allen was last seen walking into the Speed Force, leaving his friends and family behind in The Flash season 3 finale and fans are wondering whether the Scarlet Speedster will return in The Flash season 4.

Warning Spoilers Ahead

There are several fan theories about the upcoming season of The CW show, and the most popular ones include Wally West aka Kid Flash taking over Barry's place and becoming the new Flash in Central City.

Several leaked photos from The Flash season 4 have seemingly confirmed the theory. The pictures show actor Keiynan Lonsdale (who plays Wally) walking around the show's set wearing Barry's red suit with the Flash's signature mark on his chest.

Grant Gustin's character is confirmed to return for season 4, which means Wally West may have to return the Flash suit eventually in the show.

The CW network has also released the synopsis for The Flash season 4 premiere episode, which is titled, The Flash Reborn. Airing on Tuesday 10 October at 8pm EST. The official synopsis for episode 1 reads as follows:

With The Fastest Man Alive now trapped inside an extra-dimensional energy, and unknown dangers lurking in the shadows, it will be up to Team Flash to free Barry from his own personal Hell.

Earlier, Candice Patton, who plays Iris, confirmed to TV Line that The Flash season 4 picks up six months after Barry's disappearance into the Speed Force. She told the outlet at Saturn Awards, "We still don't have Barry out of the Speed Force. Iris is really struggling to deal with that, and she does it in her own way."

The first trailer and more plot details for the upcoming season is expected to be released at San Diego Comic-Con with actors and creators attending the panel, which is scheduled for 5:10-5:50 PM PST on Saturday, 22 July.