First, there's the extension of the trade deadline. In-season trades have been really infrequent in the NFL, but the Buccaneers have actually been fairly active on that front in the past years. They traded defensive end Gaines Adams for a second-round pick in 2009 and traded for DE Alex Magee in 2010. The NFL has now extended the trade deadline to week 8, which will give the Bucs a little more room to swing one of those trades. And it's possible they will. The Bucs have been steadily overhauling their roster, and that could continue into the season. If by midseason it's clear they're not going to compete for much, they may want to get rid of a valuable commodity who is not in their long-term plans. One player clearly comes to mind: Aqib Talib, but other victims could include draft picks who have underperformed.
The other relevant rule is the addition of an injured reserve exemption, which will allow one player to return from IR later in the season. This is relevant right now because of one player: Da'Quan Bowers. The talented defensive end tore his Achilles earlier this year, but he hasn't been placed on IR and the Bucs are hopeful he can make it back to play in a few games late in the season. He's likely to be placed on the PUP-list, which would allow him to come back by midseason. If his recovery takes longer, though, the Bucs are likely to place him on injured reserve. This exemption could still allow him to come back later in the season.
Finally, the NFL owners made knee and thigh pads mandatory, starting in 2013.