The most common and most likely answer to this crossword clue is the 5 plus 3 plus 6 letter word BLOCK AND TACKLE
I've seen this crossword clue in The Times
B
L
O
C
K
A
N
D
T
A
C
K
L
E
More clues leading to the result BLOCK AND TACKLE
Buddy explains!
The straight part
We know that "Tasks in game for defenders/that do the heavy lifting" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case tasks in game for defenders/that do the heavy lifting = block and tackle.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.