No official word yet, but Mark Topkin of the Tampa Bay Times just tweeted. Updates to come.
Jerry Crasnick of ESPN adds this:
Hearing that Shields, Davis and Myers aren't only names in trade. It's bigger than that, source said.
Myers won the Minor League Player of the Year award in 2012, hitting .314/.387/.600 with 37 home runs between Double and Triple-A. This leaves the Rays with Price, Hellickson, Moore and some combination of Cobb/Archer/Niemann in the rotation. They're also down a valuable bullpen arm in Davis, but we've seen Andrew Friedman be able to mine gold in that respect.
The return has been announced, via the Royals official twitter