Marvel alumni, Frank Grillo, known as Crossbones in the MCU, announced his character will reappear in "Avengers 4," but only in a flashback scene. Grillo also confirmed that "Avengers 4" will feature multiple flashback scenes that highlight significant moments in the MCU's past. Collider first reported the news from Frank Grillo.

Grillo appeared on the podcast "UFC Unfiltered" saying that "Crossbones makes an appearance in the next Avengers movie, but it's a flashback." Crossbones met his demise at the beginning of "Captain America: Civil War," when he detonated a bomb attached to his body, taking out himself and a number of innocent civilians.

While Thanos managed to eliminate half of the universe and half of the MCU, moviegoers and Marvel fans are wondering what could happen next in "Avengers 4."

Crossbones led to the fracturing of the Avengers

While Crossbones has not been seen in the MCU in a while, his death has strongly impacted the Avengers as a whole. Crossbones' actions led to the introduction of the controversial Sokovia Accords, which led to the split in the Avengers. As for what will take place in "Avengers 4," one theory that many have mentioned, is that time travel may be involved. This theory has been supported by leaked set photos that have shown Chris Evans in his original Captain America outfit. This theory would allow characters that have been killed off a chance to return.

Grillo previously said that his character's story was not complete.

Crossbones' death had a strong impact on the future of the Avengers, so it makes sense that returning to that moment in time, stopping Crossbones, and keeping Thanos from snapping his fingers, would keep the Avengers together. Fans are unsure whether the flashbacks will change the outcome for the Avengers, but it does allow fans to see a strong character that many believe was removed from the MCU too quickly.

Screen Rant said that Crossbones was originally intended to have a much larger role following "The Winter Soldier," but Marvel Studios decided to go with the "Civil War" storyline, which shortened the character ar.

Crossbones appearance hints at time travel

While Marvel has kept a tight lid on "Avengers 4," Grillo's use of "flashback," could have several implications.

The scene could have just been a cut-away to a previous point in a prior film, or could possibly open the door to a new scene that dives deeper into Crossbones or HYDRA.

Previous comments made by directors Joe and Anthony Russo have suggested that "Avengers 4" might culminate in a trip through the history of the MCU. For now, fans will just have to wait for a trailer to drop, which is rumored to be in November.