Maryland made the announcement Friday on its website.
A 19-year-old from Downingtown, Pennsylvania, Steffen led the Terrapins to consecutive regular-season and conference titles and was defensive most outstanding player at last year's NCAA College Cup, where Maryland lost to Notre Dame.
Maryland coach Sasho Cirovski says "this is a tremendous opportunity for Zack."
Other Maryland players who have signed with European clubs include Taylor Twellman and Robbie Rogers.
CONGRATS to @z_steff1 for inking a contract with @sc_freiburg of the @Bundesliga_EN! #TerpNation will miss you! http://t.co/yPiGzrHnG2
— Maryland Mens Soccer (@MarylandMSoccer) December 12, 2014
