Packed with group of players speaking in German (7)
I believe the answer is:
Here is my best explanation:
'packed' is the definition.
'group of players speaking in german' is the subsidiary indication.
'group of players' becomes 'team' (I've seen this before).
'speaking' shows a homophone (sound like).
'german' becomes 'g' (abbreviation).
'team' sounds like 'teem'.
'with' is the link.
(Other definitions for teeming that I've seen before include "Alive", "Abounding", "Abundant", "Chock-a-block", "Pouring - abounding", "Full of, abounding in", "Swarming in to meeting" and "(Of rain) falling heavily".)