The journeyman backup quarterback who was a Giant in 2010-11 made the announcement on Facebook.
The Giants acquired Rosenfels and KR/WR Darius Reynaud from the Minnesota Vikings on September 3rd, 2010 for a fifth round selection in the 2011 NFL Draft and a conditional 2012 pick, which was not exercised.
The move was made as insurance as the Giants were concerned about Eli Manning's status for the first week of the season. Eli sustained a head laceration in the third preseason game vs the Jets that required 12 stitches and was questionable for the season opener.
With David Carr gone to San Francisco, the Giants only backups were Jim Sorgi and Rhett Bomar. Sorgi had torn up his shoulder in the Jets game and was lost for the season, leaving the untested Bomar as the Giants' only healthy QB.
As it turns out, Eli was available Week 1 and Rosenfels only played in one game - mop up duty in a win over the Seahawks. Illness and injury led the Giants to release Rosenfels in October of 2011.