The NFL's owners voted today on a few new rule changes for the upcoming the season. The most significant change will be the trade deadline, which will be moved from week 6 to week 8.
By moving the deadline to midseason, we could now see a scenario where teams see themselves more as buyers or sellers. 2 games is a lot in the NFL, so by week 8 teams will have a better idea of where both they and the rest of their division are. I imagine it will lead to more dealing than we've seen at the old deadline.
The IR rules were also changed, but only a bit. Under the new rules, one player will be allowed to return to the roster from injured reserve after week 8. So this could be useful in a situation where a key player gets hurt early on and may not be ready until say... playoff time. Under the previous rules, the team would likely just IR the guy and he'd be done for the year. Now, they'll have the option to bring him back.
The Eagles may very well have used this in 2006 when Jevon Kearse was placed on IR with a knee injury after week 2. When he underwent surgery doctors found that he had dislocated his kneecap and fractured his tibia, but did not tear his ACL as was feared. It was a long injury, but he told reporters that by playoff time he was back to 100%.