Coach Ron Rivera said neither were expected to be signed on Monday, but didn't rule out that happening in the future.
Hill, a second-round pick by the New York Jets in 2012, was released on Saturday. The former Georgia Tech star has 45 career catches for 594 yards and four touchdowns.
Boone was released by the Eagles after being signed as an undrafted rookie out of LSU.
Brown made the roster as a receiver/kick returner, but his tendency to drop the ball has to be concerning despite the confidence the staff has shown in him.
Rivera said Carolina will continue to look at all positions where the team might get an upgrade.
"You gotta look at guys and see how they fit you and see if there is potential there," he said. "We have a ready list, guys we want to sign in case we get into an emergency situation."