The unbeaten 28-year-old was scheduled to face former IBF welterweight champion Devon Alexander on three different occasions before injuries to each fighter prevented the meeting from going ahead, but he is happy to still be the underdog as he looks to win a world title for the first time.
"I am a 32-0 Brit and they would prefer to fight someone else but that's why we worked hard to get the mandatory position so he has no option but to fight me," Brook told members of the media.
"The last few fights have been designed to keep me on track and focused but I have been ready for this world title shot for a long, long time.
"Shawn is the current champion and people are going to write me off, that's why I am excited because I am going to go out there to put a show on and take Porter out and bring the belt home."
Porter took the IBF belt from Alexander in December thanks to a unanimous points decision in Brooklyn.