SHIELD is apparently attacked by the Hulk, but Banner is accounted for elsewhere at the same time while this Hulk is red in color.
Did You Know?
During the Red Hulk attack, there is a conversation about the colors of the two hulks, including the line, "I heard it started out gray!" This is a reference to the first issue of the hulk comics before the character's signature skin tone was set as green. While originally this change was supposed to be ignored as an artifact of the publishing process, it was eventually made cannon. See more