Herring is an energy player, probably not a fighter at the NHL level. He is physical and very good defensively, and has been able to shut down pretty much every forward he's matched up against in the OHL and in his short stay in the ECHL last year.
He's a clutch playoff performer. Had almost as many points in a few playoff games last year in the OHL as he had in the entire regular season. He was one of the top rookie playoff performers in the ECHL playoffs, with a four point game, including a game winner, in the first round. Had a couple other multi-point games as well, I think.
People don't know about him because he had some serious injuries in major junior and lost a lot of time. Don't be surprised if he makes the team as a checking line forward who scores some tough goals from time to time.