Koblenz netted in a win over Aston Villa.
Derby County (@dcfcofficial) September 22, 2014
Derby County signed Tom Koblenz earlier this month and he is showing positive signs of progress.
The teenager signed as a free agent after leaving German club Hoffenheim's youth academy in the summer.
The 19-year-old central midfielder netted in Derby's 3-2 win over Aston Villa's under-21 side, with Ivan Calero and Alefe Santos also on the scoresheet.
The volley was Koblenz's first goal for the under-21 side in five matches.
There was however bad news for the German, as he suffered a head injury in the second half.
Tom Koblenz is down receiving treatment after a blow to the head. Looks like the German's game maybe over.— Derby County (@dcfcofficial) September 22, 2014
Tom Koblenz is stretchered off lengthy treatment and is replaced by Charles Vernam who scored in the U18s' win over Sunderland on Saturday— Derby County (@dcfcofficial) September 22, 2014
The club are yet to confirm Koblenz's injury status in the wake of the match, but given his positive start to life in the Derby youth system it would be a blow if he was to miss a substantial period of playing time.