According to the Golf Channel, a new rule requiring each player to compete in an event he had not previously played in the last four years has been approved by the PGA Tour Policy Board and will be implemented for the 2016-17 season. The penalties for not meeting the new requirement will be stiff: a fine that could exceed $20,000 and the threat of suspension.
I think it will help the events that haven't been able to put out the best of fields. The fine doesn't seem large enough, but the suspension could be a deterrent.