A familiar name on the radar of the young center back.
David Ruiz of Univision (which appears to roll up under the Spanish version of the MLS website) is saying that D.C. United defender Steve Birnbaum is on the watchlist of Bundesliga side Borussia Dortmund. It does not say that there is an offer for the 25-year old defender, but it does say that Michael Zorc is looking to fill the position left by Mats Hummels, who is returning to join Bayern Munich, where he started his career.