Miami are receiving first baseman/otufielder Jonathon Long (Cubs' No. 10 prospect) and relief pitcher Jace Beck (No. 28 prospect)
The Angels are receiving catcher Moises Ballesteros and pitching prospect Mason McGwire, the son of power-hitting legend Mark McGwire.
Chicago also acquired veteran starting pitcher Kevin Gausman in a deal with the Toronto Blue Jays (details here).
Garrett, 28, has given up seven runs in 4.1 innings of work this season for the Marlins. He's been spending most of the season in Triple-A, where he has a 2.98 ERA through 15 starts (16 games) with 83 strikeouts in 77.2 innings.
Zeferjahn, 28, has a 3.66 ERA through 45 games with 75 strikeouts in 51.2 innings. He has given up more walks (32) than hits (30) this season for the Angels.