Stadium, large, accommodates second team (7)
I believe the answer is:
arsenal
'team' is the definition.
(Arsenal football club)
'stadium large accommodates second' is the wordplay.
'stadium' becomes 'arena' ('arena' can be a synonym of 'stadium').
'large' becomes 'l'.
'accommodates' indicates putting letters inside.
'second' becomes 's' (common abbreviation).
'arena'+'l'='arenal'
'arenal' placed around 's' is 'ARSENAL'.
(Other definitions for arsenal that I've seen before include "Cache of weapons or English soccer team" , "Eleven" , "Football club and military store" , "Highbury football team" , "Munitions store and English football team" .)