NBA free agents are players whose contracts have run out. They're no longer signed to a team. They're out of work, and need a new contract, either with the same team or a new one.

Explanation of restricted NBA free agents: Players can sign with any team in the league that offers them a valid contract. They're totally free to go where they want.

Explanation of restricted NBA free agents: Players who are restricted free agents can re-sign with their most recent team, or sign an offer sheet with a new team. But if they do the latter and sign an offer sheet elsewhere then their previous team has the right to match the contract of that offer sheet and re-sign the player, whether the player wants them to or not.

There are also player options and team options. If a player's contract is a player option for the season, it means the player has the ability to "opt out" of the contract and become a free agent. And if a player's contract says that this season is a team option, then as you'd guess, the team has the option to decline the option and cause the player to become a free agent.

Key NBA Free Agent Dates: In the summer of 2013, NBA free agent negotiations begin July 1, 2013. Players and teams can negotiate, and agree to deals, but nothing can become official yet. The date NBA free agents are able to officially begin signing contracts is July 10, 2013.

2013 NBA FREE AGENTS LIST
As of June 26, 2013, these are the players that are or may become NBA free agents this summer

Atlanta Hawks: G Jeff Teague (restricted), G Devin Harris (unrestricted), G Dahntay Jones (unrestricted), G/F Kyle Korver (unrestricted), F Josh Smith (unrestricted), F Anthony Tolliver (unrestricted), F Ivan Johnson (restricted), F/C Johan Petro (unrestricted), C Zaza Pachulia (unrestricted)

Boston Celtics: F/C Chris Wilcox (unrestricted)

Brooklyn Nets: C/F Andray Blatche (unrestricted), F/G Keith Bogans (unrestricted), F Jerry Stackhouse (unrestricted), G C.J. Watson (player option/unrestricted)

Charlotte Bobcats: G Jannero Pargo (unrestricted), G Ben Gordon (player option), G/F Reggie Williams (unrestricted), G/F Gerald Henderson (restricted), F Josh McRoberts (unrestricted), F/C Byron Mullens (unrestricted), C DeSagana Diop (unrestricted)

Chicago Bulls: G Nate Robinson (unrestricted), G Marco Belinelli (unrestricted), G Daequan Cook (unrestricted), F Vladimir Radmanovic (unrestricted), F Malcolm Thomas (unrestricted), C Nazr Mohammed (unrestricted)

Cleveland Cavaliers: G Wayne Ellington (restricted), F Omri Casspi (restricted), F Luke Harangody (unrestricted), F Samardo Samuels (unrestricted), F Luke Walton (unrestricted), F Kevin Jones (unrestricted), G Kelenna Azubuike (unrestricted), G Daniel Gibson (unrestricted), G Jeremy Pargo (unrestricted), G Chris Quinn (unrestricted), G Shaun Livington (unrestricted)

Dallas Mavericks: G Darren Collison (restricted), G O.J. Mayo (unrestricted), G Rodrigues Beaubois (restricted), C Chris Kaman (unrestricted), G/F Anthony Morrow (unrestricted), F Brandan Wright (unrestricted), G Mike James (unrestricted), F Elton Brand (unrestricted)

Denver Nuggets: C Timofey Mozgov (restricted), G Julyan Stone (restricted), F Corey Brewer (unrestricted)

Detroit Pistons: G Jose Calderon (unrestricted), G Will Bynum (unrestricted), G/F Corey Maggette (unrestricted), F Jason Maxiell (unrestricted)

Golden State Warriors: G Jarrett Jack (unrestricted)

Houston Rockets: G/F Francisco Garcia (unrestricted)

Indiana Pacers: F Tyler Hansbrough (restricted), F Jeff Pendergraph (restricted), G Ben Hansbrough (unrestricted), G D.J. Augustin (unrestricted), G/F Sam Young (unrestricted), F David West (unrestricted)

Los Angeles Clippers: F Matt Barnes (unrestricted), G Chauncey Billups (unrestricted), C Ryan Hollins (unrestricted), F Lamar Odom (unrestricted), G Chris Paul (unrestricted), C Ronny Turiaf (unrestricted)

Los Angeles Lakers: F Earl Clark (unrestricted), G Devin Ebanks (restricted), G Andrew Goudelock (restricted), C Dwight Howard (unrestricted), F Antawn Jamison (unrestricted), G Darius Morris (restricted), C Robert Sacre (restricted)

Memphis Grizzlies: G Tony Allen (unrestricted), G Keyon Dooling (unrestricted), F Austin Daye (restricted), F Jon Leuer (restricted)

Miami Heat: F Juwan Howard (unrestricted), F Jarvis Varnardo (unrestricted), C Chris Andersen (unrestricted)

Milwaukee Bucks: G Brandon Jennings (restricted), G Monta Ellis (player option), G J.J. Redick (unrestricted), G/F Mike Dunleavy (unrestricted), G/F Marquis Daniels (unrestricted), C Samuel Dalembert (unrestricted), C Joel Przybilla (unrestricted)

Minnesota Timberwolves: C Nikola Pekovic (restricted), F Chase Budinger (restricted), G Brandon Roy (released), F Andrei Kirilenko, F Dante Cunningham (team option)

New Orleans Pelicans: F Al-Farouq Aminu (unrestricted), G Xavier Henry (unrestricted), G Roger Mason (unrestricted), C Louis Amundson (unrestricted)

New York Knicks: F Chris Copeland (restricted), G Pablo Prigioni (restricted), F Kenyon Martin (unrestricted), F Quentin Richardson (unrestricted), G J.R. Smith (unrestricted)

Oklahoma City Thunder: G Kevin Martin (unrestricted), G/F Ronnie Brewer (unrestricted), G Derek Fisher (unrestricted)

Orlando Magic: G Beno Udrih (unrestricted), F Hedo Turkoglu (early termination option), F DeQuan Jones (restricted) -- http://www.insidehoops.com

Philadelphia 76ers: G Charles Jenkins (restricted), C Kwame Brown (player option/unrestricted), C Andrew Bynum (unrestricted), G Royal Ivey (unrestricted), F/G Damien Wilkins (unrestricted), F/G Dorell Wright (unrestricted), F/G Nick Young (unrestricted)

Phoenix Suns: F Wesley Johnson (unrestricted), C Jermaine O'Neal (unrestricted)

Portland Trail Blazers: G Eric Maynor (restricted), F/C J.J. Hickson (unrestricted), F Luke Babbitt (unrestricted), G Elliot Williams (unrestricted), G Nolan Smith (unrestricted)

Sacramento Kings: C Cole Aldrich (unrestricted), G Toney Douglas (restricted), G Tyreke Evans (restricted), F James Johnson (restricted)

San Antonio Spurs: G Manu Ginobili (unrestricted), G Gary Neal (restricted), C DeJuan Blair (unrestricted), G/F Tracy McGrady (unrestricted), C Tiago Splitter (unrestricted) -- InsideHoops.com

Toronto Raptors: F/G Alan Anderson (unrestricted), C Aaron Gray (player option/unrestricted), G John Lucas III (team option/unrestricted), F Mickael Pietrus (unrestricted), G Sebastian Telfair (unrestricted)

Utah Jazz: C Al Jefferson, F Paul Millsap, F DeMarre Carroll, G Mo Williams, G Randy Foye, G Earl Watson, G Jamaal Tinsley, G Raja Bell, G Jerel McNeal

Washington Wizards: G Garrett Temple (restricted), G Leandro Barbosa (unrestricted), G A.J. Price (unrestricted), F Martell Webster (unrestricted), F Trevor Ariza (player option), F Cartier Martin (unrestricted), C Emeka Okafor (early termination option), C Jason Collins (unrestricted)