Getty Caleb Williams. Rookie quarterbacks in the NFL almost always go through struggles and growing pains as they attempt to adapt to what is perhaps the single most complex and difficult position to play in any sport. Hall of Famer Peyton Manning threw a league-leading 28 interceptions in his first season. Reigning NFL MVP Josh Allen of the Buffalo Bills completed only 52.8 percent of his passes as a rookie with an extremely modest passer rating of 49.8 on the season. The examples are numerous.