The upcoming NBA season remains uncertain with the terms of a new Collective Bargaining Agreement and the possibility of a lockout still looing.

While the owners and players union debate the terms of the agreement all 30 teams are held hostage, unwilling to sign players until they know those terms.

So, assuming that the two sides reach an agreement sometime before June 30 and there is no lockout, there are some quality players available.

Unlike last summer, there are no top-quality players like LeBron James, Dirk Nowitzki, Amar'e Stoudemire, Dwyane Wade, Chris Bosh, and Joe Johnson available, but teams can improve with some of these players.

Here's a look at some of this offseason's top unrestricted free agents:

Tyson Chandler C Dallas Mavericks

The 7'1 center was probably the biggest winner of the 2011 season -- playing in 74 games and starting all of them, Chandler averaged almost a double-double. He was also responsible for changing the defensive culture in Dallas, giving the Mavericks an intimidating interior presence as well as becoming a vocal leader on defense. The Mavericks will be determined to resign Chandler in the offseason, but wherever he signs he's in for a major payday.

David West PF New Orleans Hornets

West has stated that he will opt out of the last season of his contract with the Hornets. West averaged 18.9 points and 7.5 rebounds in 70 games last season, but suffered a season-ending knee injury that required surgery in April. Despite not being fully recovered, there are more than a few NBA teams that will covet the veteran's excellent midrange scoring and rebounding.

Nene C Denver Nuggets

Nene has an early termination option on his contract with the Nuggets and he will probably opt out to test his value on the free agent market. Nene averaged more than 14 points on better than 60% shooting and 70% free throw shooting last season He's only 28 and in the right system with enough touches he could be a dominant interior presence.

Jamal Crawford SG Atlanta Hawks

In his two years with the Hawks, Crawford has been an excellent scorer off the bench, winning the Sixth Man of the Year award in the 2009-2010 season. The veteran is 31 but he can still provide an excellent scoring punch for a team that needs a burst of offense, expect him to have several NBA suitors this offseason.

J.J. Barea PG Dallas Mavericks

Another winner from the Mavericks Championship run, the speedy Barea proved that he can be an offensive sparkplug off the bench. His penetration and shooting helped the Mavericks sweep the defending champion Lakers, and after he was inserted into the Mavs' starting lineup following Game Three Dallas won the next three games and the championship. The Mavs will do their best to keep him this offseason but a few teams will probably make him offers.