Muzziotti became a free agent again recently only because Major League Baseball penalized the Red Sox for trying to circumvent the rules during the previous international signing period. The Red Sox were not permitted to sign players for more than $300,000 during the 2015-16 signing period because they exceeded their bonus pool in the 2014-15 signing period.
But the Red Sox instead made package deals, essentially paying a group of players $300,000 each only to have a few of those players funnel much of their bonus to the most valuable player in the group.
Major League Baseball penalized the Red Sox for their actions, which included making the players they signed free agents.