The first-rounder was picked on in 39 snaps last week versus Detroit after taking over for Smith. Humphrey allowed five catches for 116 yards, per Pro Football Focus, including two deep shots to Marvin Jones.
"You can't tell ever how good you are until you go against some of the best guys," Humphrey said.
The rookie added he expects Roethlisberger to target him plenty when lined up against Brown.
"I'm sure if there's a weak link they have to pick out, it would definitely be me," Humphrey said, via the team's official website. "Ben likes to throw it up, he's a great quarterback, so I'm sure if he has to take those shots, it will probably be at me."
Brown is a lead-pipe lock for All-Pro honors this season, ranking first in the NFL in targets (141) receptions (88), receiving yards (1,296) and tied for first in receiving TDs (9).
It's no secret that in every key situation this season Roethlisberger will heave the ball towards Brown. The receiver still makes plays even when blanketed. Given a first-year player has been thrust into the lineup, expect the Steelers to scheme Brown into a matchup with Humphrey often.
Like any good corner, the rookie is ready for the battle.
"He's an elite receiver, everybody says the best in the league," Humphrey said. "Definitely a good challenge; I'm looking forward to it."