Susan Slusser of the San Francisco Chronicle first reported the move.
By adding Davis, the Athletics demonstrated their willingness to aim for contention in 2016.
He boosts the middle of the order in Oakland, while also deepening their outfield. Alongside Davis are Josh Reddick and Billy Burns, who project to be the Athletics' right and center fielders in 2016, respectively.
Reddick, in fact, led the 2015 Athletics in home runs, with just 20. Overall, the Atheltics' 146 home runs as a team were good for 12th (of 15) in the American League.
The 28-year-old Davis is an up-and-coming slugger who should help add to that total in 2016.
Last year, Davis hit .247/.323/.505 (122 OPS+) with 27 home runs and 66 RBIs in 440 plate appearances with Milwaukee. He ended the season on a real hot streak, homering 21 times after the All-Star break and 10 times each in the last two months of the season.
According to FanGraphs, Davis was worth 1.3 Wins Above Replacement and should only continue to get better. The Athletics have the contractual rights to Davis through 2019.
For the Brewers, the subtraction of Davis represents just another part of their teardown.
Just this offseason, Milwaukee traded the likes of Adam Lind, Jean Segura, and Francisco Rodriguez as they attempt to rebuild after finishing 68-94 in 2015.
As for their additions in this deal, Nottingham and Derby look to be legitimate pieces for the Brewers' next contending team.
Both 20, the catcher Nottingham could be the heir to Jonathan Lurcoy's position at Miller Park. A catching prospect to perhaps replace the staple in their lineup was something the Brewers lacked until now.
As for Derby, he's a little further away in terms of development, but posted a promising 1.21 ERA and a 47 to 10 strikeout-to-walk ratio in 37 1/3 innings last season, his first as a professional.