I can't imagine why MLB would want to prohibit such a move. It would substantially benefit the player (assuming he's on a split contract, which Cozens is). I'll wade into the Rule Book again...
OK. I can find nothing in either the Rules or the CBA that would prohibit recalling an optioned player who is injured, and then placing that player on the major-league Injured List.
andyb is correct that a player in the minors cannot be directly assigned to a major-league Injured List - players have to be on the Active List to be eligible for such assignment. But again, I can find nothing that would preclude recalling an optioned player (Cozens) who is on the minor-league IL - there doesn't appear to be any requirement that you can only recall players who can actually perform. (Good thing - the Phils have been routinely recalling relief pitchers from optional assignments, who clearly cannot perform at the major-league level! 
)
There is a minor-league equivalent to the 60-Day IL, called the "Emergency Injured List." However, assignment there, while it gets the player off the minor-league club's reserve list, doesn't appear to affect the major-league 40-man roster in the case of an optioned player.
