A tent could be a large plaything! (3,3)
I believe the answer is:
big top
'a tent' is the definition.
(big top is a kind of tent)
'a large plaything' is the wordplay.
'a large' becomes 'big' (I've seen this in another clue).
'plaything' becomes 'top' (top is a kind of plaything).
'big'+'top'='BIG TOP'
'could be' is the link.
(Other definitions for big top that I've seen before include "needed by Mae West, for one?" , "entertainment centre" , "Circus venue" , "'Main circus tent (3,3)'" , "performance in The Ring" .)