Most NFL players got back to work Monday, roughly a month later than in previous offseasons, under a new set of negotiated rules designed to cut injuries by reducing wear and tear on players’ bodies.

Under new rules in the league’s collective bargaining agreement, offseason programs have been reduced from 14 weeks to nine per team. The number of organized team activities, practices defined by offseason rules, has been cut from 14 to 10.

“The new rules are focused on player health and safety,” said George Atallah, assistant executive director of external affairs for the NFL Players Association. “The changes are important to ensure that players have a true offseason to rest and recover from a physically demanding profession.”

The cutbacks continue the wide-ranging effort by the league and union to reduce injury risks for players and, in particular, lower the number of hits to the head. There is no hitting among players during the offseason. Last season, contact was curbed during training camp and regular season practices.

Because last season’s lockout eliminated formal offseason activities, 2012 is the first year of the new program. NFL Commissioner Roger Goodell said the league plans to study the effects of the new provisions before reconsidering a proposal, made by the owners during the last set of labor negotiations, to lengthen the regular season from 16 to 18 games.

“I think we are going to have to go through this offseason cycle and try to see what the negotiated offseason cycle is like, the impact it has on the game, the impact it has on the individual players,” Goodell said at the annual league meeting last month in Palm Beach, Fla.

The new rules allow a player to work out on his own, if he chooses, at his team’s facilities before the offseason program begins, but prohibit him from meeting with coaches during that period.

Monday was the first day that teams — other than those with new head coaches — can begin their offseason workout programs, starting with two weeks of conditioning before more extensive on-field football-related drills start next month. Washington Redskins players are scheduled to begin their conditioning program at Redskins Park.

“I think coaches can adjust to anything,” Redskins Coach Mike Shanahan said at the league meeting late last month. With the lockout last year, as long as everybody was abiding by the same rules, you know what the rules are and you get a game plan for it. Same thing this year.”

The offseason is divided into three phases. In the first phase, which lasts two weeks, the work by players mostly is limited to strength, conditioning and rehabilitation of injuries. The second phase lasts three weeks. Players can be on the field for drills with individual instruction but there can be no offense-vs.-defense drills. The final offseason phase lasts four weeks and includes as many as 10 OTAs and one minicamp that’s mandatory for veteran players.

There is no hitting during the offseason. No pads are worn and players can wear helmets on the field only during the final offseason phase.

A team with a new head coach can start its offseason program two weeks earlier and can hold an additional voluntary minicamp prior to the NFL draft.

According to Atallah, one of the union’s goals during the labor negotiations was to put safeguards in place so teams and coaches could not overwork players year-round. Before the current labor deal took effect, most teams began their conditioning programs earlier and had busier offseason practice schedules. As many as 14 OTAs were allowed.

Jeff Fisher, the new coach of the St. Louis Rams, has expressed some concerns about how the new schedule might affect the development of a young quarterback. According to the St. Louis Post-Dispatch, Fisher said recently he thinks a quarterback should be allowed to go to a team’s facility in February and March, if he wants, to watch tape and review the playbook with a coach.

But people familiar with the union’s view said the players wanted to ensure that coaches weren’t left to their own devices, and that players weren’t pressured into participating in offseason activities officially termed voluntary.

Shanahan said he has no qualms with the new arrangement.

“Some of these rules probably will be adjusted in a year,” he said. “But for right now, we know what they are and everybody abides by the same rules.”