The most common and most likely answer to this crossword clue is the 7 plus 8 letter word REGULAR PENTAGON
I've seen this crossword clue in Independent
R
E
G
U
L
A
R
P
E
N
T
A
G
O
N
Buddy explains!
The straight part
We know that "a bit of football?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a bit of football? = regular pentagon.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.