Undrafted free agents are fighting uphill battles when they sign with the Seattle Seahawks or any other NFL team. Realistically, they are usually competing for a spot on the practice squad – and not necessarily the practice squad of the team that initially signed them. These players are usually grateful just getting the chance to compete.
To actually make an NFL roster, the UDFA would have to beat out a veteran or two, and perhaps a draft pick as well. Since the club already scouted everyone and chose to prioritize the draft pick, the UDFA has to clearly look better throughout training camp and the preseason.