Looking at Thurman vs Guerrero, and Porter vs Brook. They both seem to have gas tank problems. Thurman seems to have a bit more in the tank though. I could see Thurman stopping him probably late. Thurman also isn't a novice on the inside. He didn't really get mugged like I thought he would by Guerrero, even though he was on empty. Thurman would probably control the distance, and soften Porter up with hard body and head shots.
Vulnerability or was he just gassed? I felt it was the latter. Recall Porter gassing badly in the Brook fight. That could spell big trouble for him.