From the actual roster, only 6 players have contracts for next season: RR, PP, JJJ, EM, AB and BB (BB is team option).
From the other current staff, they can try to resign RA, KG, CW, GS and MP.
JO, KD, SP and MD won't come back.
JG will probably be back.
So far, the count is: RR, PP, JJJ, EM, AB, BB, RA, KG, CW, GS, MP and JG.
Here is a short list of a few guys (with current salaries, age and height) in FA next summer.
Power Forwards:
Michael Beasley, Minnesota Timberwolves – $6.3 million – Restricted ($8.2 million Qualifying Offer), 23, 6.10
Carl Landry, New Orleans Hornets – $8.5 million – Unrestricted, 29, 6.9
J.J. Hickson, Sacramento Kings – $2.4 million – Restricted ($3.4 million Qualifying Offer), 24, 6.9
Jason Thompson, Sacramento Kings – $3.0 million – Restricted ($4.1 million Qualifying Offer), 26, 6.11
Centers:
Roy Hibbert, Indiana Pacers – $2.6 million – Restricted ($3.7 million Qualifying Offer), 26, 7.2
Brook Lopez, New Jersey Nets – $3.1 million – Restricted ($4.2 million Qualifying Offer), 24, 7.0
Chris Kaman, New Orleans Hornets – $12.7 million – Unrestricted, 30, 7.0
JaVale McGee, Washington Wizards – $2.5 million – Restricted ($3.5 million Qualifying Offer), 24, 7.0
Robin Lopez, Phoenix Suns – $2.8 million – Restricted ($4.0 million Qualifying Offer), 24, 7.0
Spencer Hawes, Philadelphia 76ers – $4.1 million – Unrestricted, 24, 7.1
Aaron Gray, Toronto Raptors – $2.5 million – Unrestricted, 28, 7.0
At the bottom is the full list of Center players in free agency at the end of this season (source Hoopsworld).
Center (name, team – 2011-12 salary – status)
Dwight Howard, Orlando Magic – $18.1 million – Early Termination Option ($19.5 million)
Roy Hibbert, Indiana Pacers – $2.6 million – Restricted ($3.7 million Qualifying Offer)
Andrew Bynum, L.A. Lakers – $14.9 million – Team Option ($16.1 million)
Brook Lopez, New Jersey Nets – $3.1 million – Restricted ($4.2 million Qualifying Offer)
Chris Kaman, New Orleans Hornets – $12.7 million – Unrestricted
JaVale McGee, Washington Wizards – $2.5 million – Restricted ($3.5 million Qualifying Offer)
Marcus Camby, Portland Trail Blazers – $12.9 million – Unrestricted
Spencer Hawes, Philadelphia 76ers – $4.1 million – Unrestricted
Kwame Brown, Golden State Warriors – $6.8 million – Unrestricted
Aaron Gray, Toronto Raptors – $2.5 million – Unrestricted
Robin Lopez, Phoenix Suns – $2.8 million – Restricted ($4.0 million Qualifying Offer)
Jermaine O’Neal, Boston Celtics – $6.2 million – Unrestricted
Nazr Mohammed, Oklahoma City Thunder – $3.8 million – Unrestricted
Omer Asik, Chicago Bulls – $1.9 million – Unrestricted*
Semih Erden, Cleveland Cavaliers – $0.8 million – Unrestricted*
Ben Wallace, Detroit Pistons – $2.2 million – Unrestricted
Hamed Haddadi, Memphis Grizzlies – $1.3 million – Unrestricted
Mehmet Okur, New Jersey Nets – $10.9 million – Unrestricted
Jeff Foster, Indiana Pacers – $3.0 million – Unrestricted
Greg Stiemsma, Boston Celtics – $0.5 million – Unrestricted*
Daniel Orton, Orlando Magic – $1.1 million – Unrestricted*
Solomon Alabi, Toronto Raptors – $0.8 million – Team Option ($0.9 million)
Hasheem Thabeet, Houston Rockets – $5.1 million – Unrestricted*
DeSagana Diop, Charlotte Bobcats – $6.9 million – Player Option ($7.4 million)
Ryan Hollins, Cleveland Cavaliers – $2.5 million – Unrestricted
Jason Collins, Atlanta Haws – $1.3 million – Unrestricted
Eddy Curry, Miami HEAT – $1.2 million – Unrestricted
Tony Battie, Philadelphia 76ers – $1.3 million – Unrestricted
Greg Oden, Portland Trail Blazers – $1.5 million – Unrestricted
Jamaal Magloire, Toronto Raptors – $1.3 million – Unrestricted