With the way the NFL labor situation is right now, there is a good chance training camp could be shortened to only a week or two. If that does indeed happen, HBO's Hard Knocks wouldn't have a chance to capture a whole lot of footage for its show that takes viewers inside training camp every summer.
Right now, Hard Knocks actually has a bigger problem: no team wants to be on the show. The Tampa Bay Buccaneers were the first to turn down an offer to be on the show, and after that the Denver Broncos, Detroit Lions and Atlanta Falcons turned down invites.
The latest team to be offered a spot on the show only to turn it down is the Minnesota Vikings. Owner Zygi Wilf briefly explained the decision to say no to HBO, saying that the Vikings have stadium and football issues to focus on, so they don't want the distraction of the cameras and the show in general.
Perhaps teams are being extra cautious because of the lockout, but right now it seems like no team wants the distraction this year. In the past teams have been much more interested in showcasing their players and coaches to the nation, but this year teams seem much more interested in keeping things behind closed doors.