According to Bills scout Tom Roth, via BuffaloBills.com:
Catawba is a Division II school and Jumal is almost six-foot and he's a 4.50 guy. He looked really good with movement skills. He pretty much dominated Division II, which you need to do to have a chance in the NFL. He has great special teams ability. He blocked five kicks this past season, so he's going to help on special teams.
When asked to describe himself as a player by Bleacher Report's Scott Bischoff, Rolle thinks of himself as a "shutdown kind of guy," and that he "[loves] a good receiver," essentially pointing to himself as a man corner. At 5'11" and 187 pounds, he's not the biggest cornerback in the room, but he is a hard worker, which he'll need to be if he wants to make the roster.
As is the case with the Kearney signing, the Bills feel the need to add depth to their battle at cornerback, and perhaps more names to add to the emergency list.
The team announced the signing on Monday.