Chad Coleman has recently been spotted in Senoia filming Walking Dead. Apparently he has said himself that he would be playing Tyreese and will appear in the finale! Man that was a surprise! I'm only calling this legit because a lot of people who live in the area have been constantly spamming forums about this and now it's around the internet... I loved Chad Coleman in the Wire and Left 4 Dead 2, I'm certain he will pull this off.
Oh yeah, it's funny that they are FINALLY introducing him after the writers killed off T-Dog :P