Found this.. My guess was right.
"One reason IR rules became so rigid over the years is that teams like the Raiders and Redskins in the 80's used it to hide young talent. Players were told to fake injuries so the team can hoard young talent. And it occasionally is still being done, but it's not as prevalent. Coaches would instruct players to take a dive in the last pre season game and then then they got placed on IR. Then they would practice on the scout team for the entire year after taking just a week off to fake nurse the fake injury. With the expansion of the practice squad there is less need for this maneuver and the penalties from the Commissioner's office are much bigger."
I think they need to change the rule and allow a few more players to come back. Just monitor the guys on IR a little better. Make sure teams aren't putting on guys with fake injuries. I'd like then to change the inactive 7 rule as well. Cut that down to 3-4 players. Causes guys who are bubble players to not be able to play.
[ Edited by Gore_21 on Sep 12, 2013 at 3:17 AM ]