The first two undrafted Notre Dame players to sign free agent deals are long snapper JJ Jansen and running back/special teamer Travis Thomas. Jansen signed with Green Bay and Thomas signed with Cleveland.
Both probably have a pretty good chance at making a roster because they can fill niche roles on a team. Jansen is a pretty good long snapper and if he finds the right place, he can make an entire career based on long snapping. Mike Batrum is a guy who comes to mind who has lasted in the NFL for years because he’s been able to be a very effective long snapper.
Travis Thomas will make an NFL roster if he can show in camp that he can be a special teams standout. His running back skills alone will not get him on a roster and those skills alone probably wouldn’t have gotten him drafted. Because he’s played a lot of positions though, he has a chance to make a squad as a utility/special teams guy.
UPDATE: Joe Brockington has now also signed a FA deal with the Buffalo Bills.