The Brewers acquired Feyereisen from the Yankees on Sunday in exchange for minor-league infielder Brenny Escanio and international signing bonus pool money.
The 26-year-old Feyereisen was a weapon out of the Triple-A Scranton/Wilkes-Barre bullpen this season, posting a 2.49 ERA and 94:31 K:BB in 61.1 innings while holding opposing batters to a .173 average. He could be a candidate to join the big club as a September callup if the Brewers are eager to bolster their bullpen.