Taking a look at this article it would suggest that Kevin Jones is not guaranteed a roster spot and whether he is will be based on his performance in the last two games.

It's not like there is a roster spot guaranteed for the former member of the Detroit Lions. Jones will test out his surgically repaired knee for the first time in a game and said he has as much to prove to himself as the team.

Jones is coming off of an injury, it might take some time to get back into the swing of things.  If the Bears were to cut Jones for anything other than another injury it would be a huge mistake.  We have a horrible line right now and our pass game isn't looking too great.  We are going to be relying on the run game to move this machine.  We need as many able bodies as we can get.  Rookie Matt Forte looks like he could be a feature back, but we don't know for sure.  The original Adrian Peterson is a special teams ace that is a backup at best and can be an occastional fill in.  Garrett Wolfe is only a situational back.  Kevin Jones is the only proven commodity we have.  He has high potential when he is healthy.  To cast him off because of bad performances behind a shotty line in pre season is irresponsible and blatantly ignoring the needs of the team.