Yes, the off season matters. The 95th year of NFL began in September 2014 and ended in February 2015. Preparation for the 2015 season began as early as April, with voluntary offseason conditioning programs. In July the training camps will start in all seriousness.
Between the end of one season and the start of the next season’s training camp, NFL teams chalk out nine week programs for their players. The conditioning programs are mostly in 3 phases:
Phase 1 has players in physical rehabilitation, strength and conditioning programs.
Phase II includes field workouts with players. No contact and, no offense versus defense drills.
Phase III includes organized team activities. During these 10 days, teams are not allowed drills with contact, but teams are allowed a lineup of defense versus offense. During this period, teams can also have a 3 day mini camp.
Layered over this off season training, is a special schedule just for the rookies. Every team holds a rookie minicamp on the first or second weekend after the 2015 draft. Apart from this, teams schedule a seven week rookie development program usually held at the team’s facility. This is a coming of age training – from college to professional football.