MLB.com and Fox Sports cited team sources saying Upton's contract has been completed and is only pending a physical exam.
The deal for the 28-year-old former Tampa Bay Rays star is a five-year, $75.2 million package, USA Today reported.
Upton moves to the Braves after eight years and five post-season series with the Rays, for whom he batted .246 with a career-best 28 home runs over 146 games last season.
He also drove in 78 runs, stole 31 bases and registered a .454 slugging percentage while striking out a career-high 169 times.
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