The NFL granted Cravens his request for reinstatement earlier this week. The Redskins had placed the 22-year-old Cravens on the reserve/left squad list in September after leaving the team, which left him ineligible to play for the entire season.
Cravens told the Redskins he was considering retirement but never announced that his career was over.
"I definitely think there's room for Su'a on this roster, but he has to prove to the guys in that locker room that he's here for the right reasons, you know what I mean, and he wants to fight with them and he wants to go to battle," Hall said in an interview with Washington's 106.7 The Fan, via CBS DC.
"Guys have to believe he's gonna be able to be counted on, and I think this organization has to believe that, because there's nothing worse than having a guy that you have bled with and fought with and trained with, and when it's time to go to battle, they walk away. That's a tough thing for a lot of guys in this locker room to just look past."
Cravens was plagued by a knee injury when he left the team. His agent, Fadde Mikhail, issued a statement in December explaining that Cravens has been cleared to resume all football activities.
"My client suffered from Post Concussion Syndrome and, under the care of Dr. Michael Collins at the UPMC Sports Medicine Concussion Program, Su'a has undergone targeted treatment and rehabilitation," Mikhail said in the statement. "He is now asymptomatic and clear to return back to all things football. Su'a is excited and looking forward to the 2018 NFL season and the many years to follow."
Hall said he isn't ready to pass judgment until he has all the facts.
"There's not a lot of things in this league I haven't seen in the time I've been around the game," the 34-year-old Hall said. "But this is one thing that no one I've been around or I've been in the locker room with has ever experienced, and so it's all kind of new.
"So how he's gonna be received and accepted, I don't know. I know myself personally, how I would receive him -- with open arms, because I don't know the full extent of the story, and until everyone gets the full extent of the story, it's kind of hard to make an opinion. We all can voice our opinions, but to really be right, you've got to have all the information, and no one really has all the information but Su'a. I don't even think the organization has all the information."
It remains unclear whether Cravens will remain on the Redskins' roster. He has three years left on his original deal. He would count $1.7 million against the cap if he is traded or released before June 1.
Cravens was a second-round pick out of USC in 2016. He played in 11 games, including three starts, as a rookie. He had one interception and one sack.