Were the Teutonic Order ever in the Balkans? I know that several nations in the HRE, like Bohemia, offered military support whilst they were in Prussia against first the Pagans and then Poland-Lithuania.

Eric Christiansen The Northern Crusades

I'm sorry, I think you might mean the Baltics, surrounding the southern coast of the Baltic sea the Teutonic order was given land by the Polish Duke Conrad of Mazovia on the assumption that they would first help conquer and christianise the Romuva pagan tribes to the north (modern day Polish Pomerania, Leningradin Alue and Lithuania) and then submit to the Duke's overlordship.

The Balkans were the area around the southern black sea and eastern Mediterranean. Similar name and an understandable confusion.

As to answering your original question: for most of its history the HRE had a somewhat antagonistic relationship with Poland that cut off the Teutonic Order from the HRE limiting their ability to support them. Politically the Empire supplied an important ally as it supported the Order's independence (thus giving Mazovia and Poland pause in enforcing their claims on the Teutonic lands or claim of overlordship).