On Sundays in the NFL season, there are four different start times for games. The early games begin at 1 p.m. ET, and the day comes to a close with NBC's game on Sunday night at 8:20 p.m. ET. In the late afternoon slot, games start at either 4:05 p.m. ET or 4:15 p.m. ET.
Starting this upcoming season, there will be a change to one of the usual start times. Specifically, the start times for late doubleheaders will be 4:25 p.m. ET instead of 4:15. The change is being made in order for there to be more of a gap between the early and late games in doubleheaders. From the NFL:
The 4:25 PM ET kickoff time will reduce instances in which fans miss the end of a 1:00 PM ET game telecast because they must receive the opening kickoff of their home team’s late-afternoon game. In addition, fans not in the cities of the late doubleheader opponents will be less likely to miss the beginning of the late doubleheader game.
This change won't affect the Lions, as they didn't have any games scheduled to start at 4:15 p.m. ET in 2012. In fact, they only have one late afternoon game scheduled in 2012 -- a 4:05 p.m. ET start at the Arizona Cardinals on Dec. 16.