In a mad scramble to prepare for the season, NFL players returned to practice facilities Tuesday, coaches hurriedly made final arrangements for training camps and general managers scurried to assemble rosters by juggling phone calls with agents.

“If you look under ‘multi-tasking’ in the dictionary, you’re going to see pictures of NFL agents, players, teams, GMs, coaches, everyone in the entire sport today,” veteran agent Peter Schaffer said in an afternoon telephone interview. “It’s about six months of work crammed into a few days.”

There was little time to waste on the heels of Monday’s announcement that the sport would resume operations after player leaders started their approval process of a new 10-year collective bargaining agreement with the league.

For nearly 41 / 2 months, the lockout shut down the NFL. Trades of players and free agent signings were on hold. Coaches were prohibited from talking to players and players were barred from teams’ facilities, other than briefly in late April between a federal judge’s decision to grant an injunction halting the lockout and an appeals court’s ruling to keep that injunction from taking effect.

Players were back to work Tuesday, presumably to stay this time.

“Guys I’ve seen today look pretty good [but] obviously we haven’t taken one step in a competitive situation,” Arizona Cardinals Coach Ken Whisenhunt said at a news conference.

Getting players back into football-playing condition after an offseason without official practices will be a primary task for NFL coaches, who also must deal with new rules limiting the amount of hitting in some practices. Ten NFL teams are scheduled to open training camps Wednesday, followed by 10 more Thursday, 10 Friday and the final two Sunday.

“It’s going to take some adjustment,” Buffalo Bills Coach Chan Gailey said at a news conference. “But almost everybody in the league will have to adjust because most of these head coaches have been in the league for quite a while. So everybody’s going to go through this period of adjustment, and it’s probably going to have to experience it for a year — the whole year — before you get a full handle on how you have to do things differently.”

Coaches weren’t alone in trying to figure things out. Players also were trying to get their bearings.

“I’m still hearing a lot of it and finding out what we can and can’t do, what practices are going to be like. . . . I think a lot of that is going to be learned on the run,” New York Jets quarterback Mark Sanchez said at a news conference.

Teams were permitted to begin signing rookies Tuesday. They also could negotiate with veteran free agents and line up deals, although those players cannot officially be signed until 6 p.m. Friday.

“We’re working on a bunch of deals,” Schaffer said. “A lot of things are moving. It’s a ton of moving parts. If you love what you’re doing, it’s fun. I’m having a blast.”

Bills General Manager Buddy Nix said he found out a little before 7 p.m. Monday, just as he and other club officials were about to leave for dinner, that teams could begin to negotiate with undrafted rookies. So he and other club officials got busy lining up deals with rookie free agents that could be completed Tuesday.

“The rule changes every 30 minutes it seems like. . . . We just adjust on the fly,” Nix said at the Bills’ news conference. “It really is a little difficult, but everybody’s got the same problem.”

Teams devoted some of their energies Tuesday to making cutbacks to ensure compliance with the salary cap, set for $120.4 million per team for the upcoming season. Players around the league were informed they would be released, although those moves won’t become official until 4 p.m. Thursday when the waiver system takes effect. There were reports that the Dallas Cowboys planned to release wide receiver Roy Williams, running back Marion Barber and guard Leonard Davis.

The Cardinals and other teams were said to be pursuing a possible trade for Philadelphia Eagles quarterback Kevin Kolb. Hundreds of free agents will be looking for teams, with the class perhaps headed by Oakland Raiders cornerback Nnamdi Asomugha.

Some veteran free agents began agreeing to deals Tuesday. Defensive end Charles Johnson agreed to a six-year contract worth more than $70 million to remain with the Carolina Panthers, and other players also had deals in place.

Teams will be put together on the run, creating unprecedented disorder for a sport that usually relies on a familiar calendar.

Whisenhunt said that coaches will have to be patient with young players. The first round of preseason games is scheduled for Aug. 11-15, and Whisenhunt said those games will be “a real eye-opening experience for those guys.”

But Whisenhunt also said, “It’s exciting to get back to football.”