Midfielders Astrit Ajdarevic, Levi Porter and James Wesolowski and striker DJ Campbell were among the omissions.
Ajdarevic being overlooked could be seen as a surprise after the former Liverpool youth player signed a one-year deal at the Walkers Stadium following a successful loan spell last season.
Campbell has been heavily linked with a move away from the club while Porter and Wesolowski have failed to force their way into Pearson's plans after long-term injuries.
Pearson said: "The onus is on the players not in the list. If they progress and make it into the first-team, they will get a squad number."