Jesse D. Garrabrant/Getty Images

The JaVale McGee era in Philadelphia was brief but entertaining. Now, after nearly signing with the Boston Celtics, McGee will remain a free agent. 
Steve Bulpett of the Boston Herald reported that talks between McGee and the Celtics fell apart:

JaVale McGee will NOT be coming to the Celtics. The sides couldn’t reach agreement on a contract.
— Steve Bulpett (@SteveBHoop) March 5, 2015
Adrian Wojnarowski of Yahoo Sports reported the option for next season prevented the deal from getting done:

JaVale McGee and Boston couldn’t agree on option for next season, league source tells Yahoo. Celtics wanted team option; McGee player option
— Adrian Wojnarowski (@WojYahooNBA) March 5, 2015
Earlier in the day, David Aldridge of TNT reported the Celtics had signed McGee to a contract, while Jeff Goodman of ESPN.com reported the deal would extend through next season. 
Goodman passed along general manager Danny Ainge’s thoughts on McGee:

JaVale is a long, athletic guy, and we don’t have that type of player — an above-the-rim offensive and defensive player. He’s been paid a lot of money in our league, had some injuries, hasn’t lived up to his potential yet, and we’re hoping that he can under [Celtics coach Brad Stevens’] tutelage.

This came after the Philadelphia 76ers waived him on March 2, per Sam Amick of USA Today. McGee played six games for the Sixers, scoring 18 points and grabbing 13 boards in 61 minutes on the floor. Philadelphia acquired him and a first-round pick just before the trade deadline.
Given the state of the 76ers, it seemed only a matter of time before McGee was either bought out or waived outright.
He seemed reluctant to the idea of agreeing to a buyout upon joining up with Philly, per ESPN.com’s Marc Stein:

I don’t want to get bought out. That’s not a positive thing. When you think about it, you don’t get all of your money when you get bought out. So it doesn’t make sense why someone would want to get bought out unless they are older—older and they want to go to a contender or something. I’m not that old. I just want to play basketball.

McGee got a bit lucky in that he’ll still receive the full money owed to him over the next two years. The 76ers also released him in time for him to join up with a …Read More