The Raiders placed the tag on Branch on March 1 and he was unable to join the team until signing the tender or reaching a long-term contract.
The two sides are still hoping to reach a long-term deal before a July 15 deadline to give the Raiders more salary cap room and Branch more stability.
Getting Branch signed and with the team was important for the Raiders, who are counting on him to be one of the defensive leaders under a new defense run by head coach Dennis Allen and coordinator Jason Tarver.
Branch, a fourth-round pick in 2008, has started every game the past three seasons and led the Raiders in tackles the past two years. He had 78 solo tackles, one sack, one interception, four passes defensed and one fumble recovery last season.
Branch's 327 total tackles over the past three seasons are the second most of any NFL defensive back, trailing only Indianapolis' Antoine Bethea, who has 340.
Branch also was much improved in pass coverage, cutting his completion percentage against from 67.4 percent in 2010 to 55.7 percent last season, according to STATS LLC, as the Raiders often used him as a cornerback in nickel packages.
Branch and free safety Michael Huff will anchor an overhauled secondary in Oakland this year. After years of running a defense premised on aggressive man coverage under late owner Al Davis, the Raiders are expected to use more blitzes and zone coverages this season.
The Raiders are still waiting for fullback Marcel Reece to sign his exclusive rights tender.