The NBA owners aren't the only ones looking to alter the landscape of the league over the next several seasons through the league's collective bargaining agreement.

While the owners want to do away with the soft salary cap and guaranteed contracts, the players hope to end the age restriction that forbids players from entering the NBA directly out of high school.

"We want to go back to the way it was," a source from the National Basketball Players Association said. "The players have always been philosophically opposed to it. The vast majority of players feel a player should have the right to make a living. If he has the talent and wants to make money to help his family, he should have that right. It's just a matter of principle."

NBPA executive director Billy Hunter sent an audio podcast detailing the union's proposal to every player last week. The proposal, which includes the end of the age restriction, has been obtained by ESPN.com and confirmed by a union source.

In its proposal, the union, while rejecting the owners' call for a hard salary cap and salary reductions, is also willing to negotiate a reduction in league revenue guarantees for players. The union also proposes rule changes that would provide more flexibility for sign-and-trade deals.

The age restriction, which requires a player to be at least 19 years old during the calendar year of the draft as well as at least one year removed from his high school graduation class, has been in place since the 2005-2006 season. A league spokesman refused to comment when asked Wednesday about the union's proposed change to the age restriction.

The league did not address the age requirement specifically in the collective bargaining proposal it submitted to players in February. But commissioner David Stern's desire has long been to raise the minimum age to 20 rather than to lower it.

NBA spokesman Mike Bass refused to comment when contacted by ESPN.com.

While there are much larger issues separating the sides, the age restriction could become a bargaining chip in the stalemated negotiations between owners and players that appear headed toward a lockout next summer.

Hunter said last month he's "99 percent sure" there will be a lockout, and a look at the proposals of each side reveals Hunter may have underestimated the chances of a work stoppage.

The union submitted its contract proposal in July, but it seems to have barely registered with the owners, who have neither provided a counterproposal nor backed off the demands they made in February. The league also refused to comment Wednesday on the details of the union's proposal.

"Our proposal was designed to move the negotiations forward, to be a win-win for both sides," the union source said. "We looked to address some of the owners' concerns and the proposal had elements that would benefit both sides. But the owners have sat on this for five months."

While the union rejects the owners' demands for a hard cap, an $800 million cut in salaries, a shortening of contract lengths and an elimination of guaranteed contracts, it is willing to negotiate a reduction in the percentage of league revenue players are guaranteed.

Players are currently guaranteed 57 percent of basketball-related income, and the players are willing to remove that guarantee. No new figure was proposed by the union, which is also open to considering adjustments to revenue formulas for owners who build new arenas or significantly renovate existing ones.

The players' association also proposed, according to the podcast, "enhanced trade and signing flexibility." Basically, it wants to change the system in a way that would make it easier for teams to make trades.

Currently, in trades involving a team that is above the salary cap, the traded players' salaries must fall within 125 percent of one another. The union would like to at least double that percentage. That would make it easier for cash-strapped clubs to receive financial relief by trading away players with large contracts.

The union suggests ending the complicated "base-year compensation" rule that often makes it difficult to pull off trades.

"We want to keep the current system in place, and address some of the owners' concerns within the context of that system," the source said. "We want to keep the soft cap we've had for 30 years and keep salaries tied to revenues."

In the past, the players have had no say in how the owners have shared their revenue among themselves. But with the owners complaining about millions of dollars in annual losses, the union proposed in July that the league incorporate "meaningful revenue sharing."

The players do not believe the burden for giving small-market clubs financial relief should fall entirely upon them. Thus, they're proposing that the league share not only national revenue -- such as television contracts, sponsorships and gate receipts -- but local revenue as well.

The union also suggests the league could give small markets a larger share of the national revenue.

Staunchly against a hard cap, which would eliminate longtime collective bargaining staples such as the Larry Bird exception, the union also noted that it wants to not only keep the midlevel exception but add a second midlevel exception.

In exchange, the players would give up the "bi-annual exception," which is currently worth $2 million, and decrease the maximum length of midlevel contracts from five years to four years.

The players are also looking to shorten the time period (currently seven days) that teams have to match offers for restricted free agents, as well as gain better pension benefits.

The union has been anticipating a lockout for more than a year and has been advising its players regularly to save money in preparation for a work stoppage.

The players are ready to fight to keep the key elements of the current system, as evidenced by the attendance of superstars such as LeBron James, Dwyane Wade, Carmelo Anthony and Chris Paul at a negotiating meeting in August.

The players were galvanized in part after union representatives showed them PowerPoint presentations that explained exactly how much money they would lose if the owners' proposal was accepted. For instance, the $18 million Joe Johnson is slated to make next season would fall to about $11 million under the owners' proposed system, with less than $5 million guaranteed.

The owners are digging in as well, with one source close to several owners saying "they will not budge" from their current proposal. If the two sides haven't moved significantly closer to one another by the February All-Star break, a lockout would seem inevitable.

"We're not planning to make another proposal, in part because the owners have not made a counterproposal," the union source said. "They don't seem to want to make a deal early."

Chris Broussard covers the NBA for ESPN The Magazine.