Players were locked out a month after last season's Super Bowl, won by the Green Bay Packers [GALLO/GETTY]

Sources from within the NFL lockout negotiations have told the Associated Press news agency that an agreement was reached in the early hours of Monday morning.

Players were expected to begin the voting process later in the day.

The agency said the sources spoke on condition of anonymity because the process was supposed to remain secret and no formal announcement had been made.

The NFL Players Association's (NFLPA) executive committee was to meet Monday to be presented with the finalised agreement.

Owners overwhelmingly approved a proposal last week, but some unresolved issues still needed to be amended to satisfy players.

The league's old labour deal expired in March, and the owners locked out the players – the NFL's first work stoppage since 1987.

"We have every reason to believe it's going to be a good day," NFL spokesman Greg Aiello wrote in an email to the Associated Press.

If players sign off on the agreement, NFL clubs would be able to start signing 2011 draft picks and rookie free agents on Tuesday.

Conversations with veteran free agents also could start, and signings could begin on Friday.

Under that tentative schedule, training camps would open for 10 of the 32 teams on Wednesday, 10 teams on Thursday, another 10 teams on Friday, and the last two teams on Sunday.

The major economic framework for the deal was worked out more than a week ago.

Revenues

That included how the more than $9 billion in annual league revenues will be divided.

About 53 per cent will go to owners and 47 per cent to players over the next decade; the old agreement resulted in nearly a 50-50 split.

There is also a per-club cap of about $120 million for salary and bonuses in 2011 – and at least that in 2012 and 2013 – plus about $22 million for benefits; a salary system to rein in spending on first-round draft picks; and unrestricted free agency for most players after four seasons.

Should the players' executive committee vote to accept the deal, it then would go to the 32 team representatives to approve, perhaps later on Monday.

After that, the total membership would need to vote, with a simple majority required for passage.

Also, the 10 named plaintiffs in a players' lawsuit against the league – including Tom Brady, Peyton Manning and Drew Brees – must officially inform the court in Minneapolis of their approval of the pact.

Even after that, while training camps would be opened, a true collective bargaining agreement can't be finalised until the NFLPA re-establishes itself as a union.

Players will need to vote to do so even as the sides put the finishing touches on a deal; only after the NFLPA is again a union can it negotiate such items as the league's personal conduct policy and drug testing.