Driver-12 years ago, I signed my first big contract with Packers, and promised I'd never play in another uniform. Today we make it officialHe's had a great career but it's time. Actually I'm really impressed on how well he's timed it. Though he was only a bit player in 2011, he still had a good season and his career didn't seem over. Obviously the Packers thought the same because they brought him back for 2012. But Driver himself knew it couldn't last forever, telling reporters in May 2012 that he would only play for one or two more seasons.
— Green Bay Packers (@packers) February 6, 2013
And he vanished by the end of the 2012 season. The fact that he couldn't play ahead of WR Jarrett Boykin and WR Jeremy Ross was an obvious sign of decline. Part of him might think he can still play and start in the NFL, but the odds are that he can't. Instead, he's leaving on a high note, having won a Super Bowl ring in 2011 and play for two more full seasons. If he hadn't retired, he would have gone through the process of trying to stay when the Packers most likely did want him to return.
A Lambeau Field hosted retirement announcement, with all the Packers' past and present team leaders (plus the Governor) was an appropriate send-off for one of their best all-time players.