USA Basketball Managing Director Jerry Colangelo has mandated that all 2016 Olympic hopefuls must attend this mini-camp. Thus, it's pretty easy to assume that Durant wants to be a part of Team USA during 2016.
The injury news is a little bit worrisome. Durant reportedly trained with teammates from July 20th-23rd. There was no word on the intensity of that training, or the specifics of what KD was able to do. According to an earlier report, Durant was expecting to be fully cleared to play by some time in August. In any case, Durant's sitting out now may simply be precautionary.
Russell Westbrook has not been mentioned as a potential invitee yet. USA Basketball has not officially announced who's going to be there, so Westbrook could very well still be going. It's all up in the air at this point.
Previously, Durant and Westbrook participated on Team USA during the 2010 FIBA World Championship and 2012 Olympics. Durant was originally slated to participate during 2014, but pulled out midway through training camp. Westbrook turned Team USA down before training camp started, but still visited the team during practice in Las Vegas.