The team had hoped to lock Branch down long term but if a long term deal was unable to be made come the franchise tag deadline, they would tag him rather than risk losing him as a free agent come the March 13 free agent period.
The franchise tag will allow the team the necessary time to continue to work on a long term deal with Branch. The tag carries with it $6.2 million in 2012-all of which is guaranteed. The best case scenario would be to get him signed long term before the end of the March 13 so the team could lower his 2012 cap number.
Placing the tag on Branch also means Michael Bush will most certainly enter the free agent market. The team was unlikely to put the tag on Bush anyway considering his tag number would have been upwards of $7.7 million next season. Which not only is $1.5 million more than the tag amount for Branch but would mean Bush's base salary would be higher than that of the presumed starting running back, Darren McFadden.