According to NFL Network's Ian Rapoport, the suspension stems from Jones' arrest last October when he was pulled over and admitted that he had smoked marijuana. Jones later pleaded no contest to a marijuana-related charge.
This may be a blessing in disguise. It will allow the Packers to keep an extra player coming out of training camp and have a quality roster add if someone is injured in the first 2 weeks. They have enough depth to carry the load until his return in week 3.